Vibration Analysis \u2014 Beginner's Guide to Spectrum Diagnostics \u2014 Vibromera<\/title>\n<meta name=\"description\" content=\"Complete vibration analysis guide: FFT spectrum interpretation, fault diagnosis (unbalance, misalignment, looseness, bearing defects), bearing frequency calculator (BPFO\/BPFI\/BSF\/FTF), ISO 10816 severity assessment, and interactive spectrum demos with Balanset-1A.\">\n<meta name=\"keywords\" content=\"vibration analysis, FFT spectrum, vibration diagnostics, bearing defect frequency, BPFO, BPFI, BSF, FTF, unbalance diagnosis, misalignment spectrum, mechanical looseness, predictive maintenance, ISO 10816, Balanset-1A, vibration analyzer, condition monitoring\">\n<meta name=\"author\" content=\"Vibromera\">\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large\">\n\n\n\n\n\n\n\n<meta property=\"og:type\" content=\"article\">\n<meta property=\"og:title\" content=\"Vibration Analysis \u2014 Spectrum Diagnostics Guide with Interactive Tools\">\n<meta property=\"og:description\" content=\"FFT spectrum interpretation, bearing frequency calculator, ISO 10816 severity checker, fault diagnosis patterns \u2014 complete beginner's guide with Balanset-1A.\">\n<meta property=\"og:url\" content=\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/\">\n<meta property=\"og:site_name\" content=\"Vibromera \u2014 Vibration Analysis & Balancing Equipment\">\n<meta property=\"og:locale\" content=\"en_US\">\n<meta property=\"og:image\" content=\"https:\/\/vibromera.eu\/wp-content\/uploads\/vibration-analysis-og.jpg\">\n<meta property=\"article:publisher\" content=\"https:\/\/vibromera.eu\/\">\n<meta property=\"article:section\" content=\"Glossary\">\n<meta property=\"article:tag\" content=\"Vibration Analysis\">\n<meta property=\"article:tag\" content=\"FFT Spectrum\">\n<meta property=\"article:tag\" content=\"Predictive Maintenance\">\n<meta name=\"twitter:card\" content=\"summary_large_image\">\n<meta name=\"twitter:title\" content=\"Vibration Analysis Guide \u2014 FFT, Bearing Frequencies & Fault Diagnosis\">\n<meta name=\"twitter:description\" content=\"Interactive bearing frequency calculator, ISO 10816 checker, FFT spectrum demos, and step-by-step fault diagnosis for rotating machinery.\">\n<meta name=\"geo.region\" content=\"EU\">\n<meta name=\"geo.placename\" content=\"Porto, Portugal\">\n<meta name=\"geo.position\" content=\"41.1579;-8.6291\">\n<meta name=\"ICBM\" content=\"41.1579, -8.6291\">\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@graph\":[\n{\"@type\":\"TechArticle\",\"@id\":\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/#article\",\"headline\":\"Vibration Analysis: Beginner's Guide to Spectrum Diagnostics with Balanset-1A\",\"description\":\"Comprehensive guide to vibration analysis and FFT spectrum interpretation for rotating machinery diagnostics. Covers unbalance, misalignment, looseness, bearing defects, gear faults with interactive calculators and spectrum demonstrations.\",\"author\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\"},\"publisher\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\",\"logo\":{\"@type\":\"ImageObject\",\"url\":\"https:\/\/vibromera.eu\/wp-content\/uploads\/vibromera-logo.png\"}},\"mainEntityOfPage\":\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/\",\"datePublished\":\"2025-09-15\",\"dateModified\":\"2026-02-07\",\"inLanguage\":\"en\",\"proficiencyLevel\":\"Beginner\",\"about\":[{\"@type\":\"Thing\",\"name\":\"Vibration Analysis\"},{\"@type\":\"Thing\",\"name\":\"FFT Spectrum Analysis\"},{\"@type\":\"Thing\",\"name\":\"Predictive Maintenance\"},{\"@type\":\"Thing\",\"name\":\"Bearing Defect Frequencies\"}]},\n{\"@type\":\"FAQPage\",\"@id\":\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/#faq\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"What is vibration analysis?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Vibration analysis is the process of measuring and interpreting mechanical oscillations of rotating machinery to diagnose faults. Using FFT (Fast Fourier Transform), the complex vibration signal is decomposed into individual frequency components. Each fault type produces a characteristic 'fingerprint' in the frequency spectrum \u2014 unbalance at 1\u00d7 RPM, misalignment at 2\u00d7, looseness as multiple harmonics, bearing defects at non-synchronous frequencies (BPFO, BPFI, BSF, FTF).\"}},\n{\"@type\":\"Question\",\"name\":\"How do I know if vibration is caused by unbalance or misalignment?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Unbalance produces a dominant peak at exactly 1\u00d7 RPM (shaft speed) in the radial direction, with stable phase and amplitude proportional to speed\u00b2. Misalignment produces significant 2\u00d7 RPM component (often equal to or larger than 1\u00d7), strong axial vibration, and 180\u00b0 phase shift across the coupling.\"}},\n{\"@type\":\"Question\",\"name\":\"What are bearing defect frequencies (BPFO, BPFI, BSF, FTF)?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"These are characteristic frequencies generated when a rolling element passes over a defect on a specific bearing component. BPFO (Ball Pass Frequency Outer race), BPFI (Ball Pass Frequency Inner race), BSF (Ball Spin Frequency), FTF (Fundamental Train Frequency). They depend on bearing geometry and shaft speed.\"}},\n{\"@type\":\"Question\",\"name\":\"What is a good vibration level for rotating machinery?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"ISO 10816-1 classifies vibration severity by machine class. For typical industrial machines (Class II, 15-75 kW): Zone A (good) < 1.8 mm\/s RMS, Zone B (acceptable) < 4.5 mm\/s, Zone C (alert) < 11.2 mm\/s, Zone D (danger) > 11.2 mm\/s.\"}},\n{\"@type\":\"Question\",\"name\":\"Can the Balanset-1A be used for vibration analysis?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes. The Balanset-1A includes a 2-channel vibration analyser with FFT spectrum display (F1 mode), vibrometer for overall\/1\u00d7 comparison (F5 mode), and detailed spectrum charts (F8 mode). Both channels can be used simultaneously for radial+axial comparison.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the difference between time waveform and FFT spectrum?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The time waveform shows vibration amplitude over time \u2014 complex when multiple faults are present. FFT decomposes this into individual frequency components, creating a spectrum where each peak corresponds to a specific source.\"}},\n{\"@type\":\"Question\",\"name\":\"How often should I measure vibration?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Critical equipment: weekly or biweekly. Standard production: monthly. Auxiliary\/non-critical: quarterly. After any maintenance: immediately to establish new baseline.\"}},\n{\"@type\":\"Question\",\"name\":\"What causes subharmonic vibration (0.5\u00d7)?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Subharmonics at 0.5\u00d7 RPM typically indicate severe mechanical looseness, oil whirl in journal bearings, or cracked shafts. 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.formula-main{font-size:16px}.shop-cta h2{font-size:24px}}\n@media(max-width:480px){.hero h1{font-size:24px}.quick-nav a{padding:12px 12px;font-size:13px}.fault-grid{grid-template-columns:1fr}.units-grid{grid-template-columns:1fr}}\n@media print{.quick-nav,.shop-cta,.toc-sidebar,.demo-panel,.calc-panel{display:none}}\n<\/style>\n<\/head>\n<body>\n\n<header class=\"hero\">\n<div class=\"hero-inner\">\n<div class=\"breadcrumb\"><a href=\"https:\/\/vibromera.eu\/\">Home<\/a> \u2192 <a href=\"https:\/\/vibromera.eu\/glossary\/\">Glossary<\/a> \u2192 Vibration Analysis<\/div>\n<h1>Vibration Analysis \u2014 <span>Spectrum Diagnostics<\/span> Guide<\/h1>\n<div class=\"canon-badge\"><span style=\"font-size:14px;\">\ud83d\udccc<\/span> Canonical Reference Article \u2014 vibromera.eu<\/div>\n<p class=\"subtitle\">From FFT fundamentals to fault diagnosis: learn to read vibration spectrums, calculate bearing defect frequencies, assess severity per ISO 10816, and diagnose unbalance, misalignment, looseness, bearing and gear defects \u2014 with interactive tools and the Balanset-1A.<\/p>\n<\/div>\n<\/header>\n\n<nav class=\"quick-nav\"><div class=\"quick-nav-inner\">\n<a href=\"#calculators\">\ud83e\uddee Calculators<\/a>\n<a href=\"#fft-demo\">\ud83d\udcca FFT Demo<\/a>\n<a href=\"#fault-table\">\ud83d\udd0d Fault Table<\/a>\n<a href=\"#fundamentals\">\ud83d\udcd0 FFT Basics<\/a>\n<a href=\"#units\">\ud83d\udcca Units<\/a>\n<a href=\"#measurement\">\ud83d\udccf Measurement<\/a>\n<a href=\"#unbalance\">\u2696 Unbalance<\/a>\n<a href=\"#misalignment\">\ud83d\udd27 Misalignment<\/a>\n<a href=\"#looseness\">\ud83d\udd29 Looseness<\/a>\n<a href=\"#bearings\">\ud83d\udd35 Bearings<\/a>\n<a href=\"#gears\">\u2699 Gears<\/a>\n<a href=\"#belt\">\ud83d\udd17 Belts<\/a>\n<a href=\"#cavitation\">\ud83d\udca7 Cavitation<\/a>\n<a href=\"#oilwhirl\">\ud83c\udf00 Oil Whirl<\/a>\n<a href=\"#phase\">\ud83e\udded Phase<\/a>\n<a href=\"#envelope\">\ud83d\udce1 Envelope<\/a>\n<a href=\"#iso-full\">\ud83d\udccb ISO 10816<\/a>\n<a href=\"#monitoring\">\ud83d\udcc8 Monitoring<\/a>\n<a href=\"#faq\">\u2753 FAQ<\/a>\n<\/div><\/nav>\n\n\n<section class=\"section-bg\" id=\"calculators\">\n<div class=\"container\">\n<div class=\"section-header\">\n<h2>Interactive Diagnostic Calculators<\/h2>\n<p>Essential tools for vibration analysis \u2014 bearing defect frequencies, gear mesh frequency, severity assessment, and unit conversion<\/p>\n<\/div>\n<div class=\"calc-grid\">\n\n\n<div class=\"calc-panel\">\n<div class=\"calc-header\">\ud83d\udd35 Bearing Defect Frequency Calculator<\/div>\n<div class=\"calc-body\">\n<div class=\"calc-form\" id=\"bearing-calc-form\">\n<div>\n<label>Quick Select \u2014 Common Bearing<\/label>\n<select id=\"bc-preset\" onchange=\"applyBearingPreset()\">\n<option value=\"\">\u2014 Manual entry \u2014<\/option>\n<optgroup label=\"62xx Series (Light)\">\n<option value=\"9,7.938,38.5,0\">6200 \u2014 9 balls, Bd 7.94, Pd 38.5<\/option>\n<option value=\"7,7.938,25.4,0\">6201 \u2014 7 balls, Bd 7.94, Pd 25.4<\/option>\n<option value=\"8,7.938,32.0,0\">6202 \u2014 8 balls, Bd 7.94, Pd 32.0<\/option>\n<option value=\"8,9.525,34.0,0\">6203 \u2014 8 balls, Bd 9.53, Pd 34.0<\/option>\n<option value=\"8,7.938,33.5,0\">6204 \u2014 8 balls, Bd 7.94, Pd 33.5<\/option>\n<option value=\"9,7.938,38.5,0\">6205 \u2014 9 balls, Bd 7.94, Pd 38.5<\/option>\n<option value=\"9,9.525,46.0,0\">6206 \u2014 9 balls, Bd 9.53, Pd 46.0<\/option>\n<option value=\"8,11.112,53.5,0\">6207 \u2014 8 balls, Bd 11.11, Pd 53.5<\/option>\n<option value=\"9,11.906,60.0,0\">6208 \u2014 9 balls, Bd 11.91, Pd 60.0<\/option>\n<option value=\"8,12.7,65.0,0\">6209 \u2014 8 balls, Bd 12.70, Pd 65.0<\/option>\n<option value=\"10,12.7,70.0,0\">6210 \u2014 10 balls, Bd 12.70, Pd 70.0<\/option>\n<\/optgroup>\n<optgroup label=\"63xx Series (Medium)\">\n<option value=\"7,11.112,34.85,0\">6305 \u2014 7 balls, Bd 11.11, Pd 34.9<\/option>\n<option value=\"8,11.509,43.5,0\">6306 \u2014 8 balls, Bd 11.51, Pd 43.5<\/option>\n<option value=\"8,13.494,50.0,0\">6307 \u2014 8 balls, Bd 13.49, Pd 50.0<\/option>\n<option value=\"8,15.081,58.5,0\">6308 \u2014 8 balls, Bd 15.08, Pd 58.5<\/option>\n<option value=\"8,17.462,65.0,0\">6309 \u2014 8 balls, Bd 17.46, Pd 65.0<\/option>\n<option value=\"8,19.05,72.5,0\">6310 \u2014 8 balls, Bd 19.05, Pd 72.5<\/option>\n<\/optgroup>\n<optgroup label=\"NU \/ NJ Series (Cylindrical Roller)\">\n<option value=\"13,9.0,42.5,0\">NU 205 \u2014 13 rollers, Bd 9.0, Pd 42.5<\/option>\n<option value=\"12,10.0,52.0,0\">NU 206 \u2014 12 rollers, Bd 10.0, Pd 52.0<\/option>\n<option value=\"14,10.0,52.0,0\">NU 208 \u2014 14 rollers, Bd 10.0, Pd 52.0<\/option>\n<\/optgroup>\n<optgroup label=\"Tapered Roller\">\n<option value=\"17,8.73,45.5,14\">30205 \u2014 17 rollers, Bd 8.73, Pd 45.5, \u03b1 14\u00b0<\/option>\n<option value=\"17,10.4,54.5,14\">30206 \u2014 17 rollers, Bd 10.4, Pd 54.5, \u03b1 14\u00b0<\/option>\n<option value=\"17,12.15,63.0,14\">30208 \u2014 17 rollers, Bd 12.15, Pd 63.0, \u03b1 14\u00b0<\/option>\n<\/optgroup>\n<\/select>\n<\/div>\n<div class=\"calc-row\">\n<div><label>Shaft Speed (RPM)<\/label><input type=\"number\" id=\"bc-rpm\" value=\"1500\" min=\"1\"><\/div>\n<div><label>Number of Rolling Elements (n)<\/label><input type=\"number\" id=\"bc-balls\" value=\"9\" min=\"2\"><\/div>\n<\/div>\n<div class=\"calc-row\">\n<div><label>Ball \/ Roller Diameter, Bd (mm)<\/label><input type=\"number\" id=\"bc-bd\" value=\"7.938\" step=\"0.001\" min=\"0.1\"><\/div>\n<div><label>Pitch Diameter, Pd (mm)<\/label><input type=\"number\" id=\"bc-pd\" value=\"38.5\" step=\"0.1\" min=\"1\"><\/div>\n<\/div>\n<div><label>Contact Angle, \u03b1 (degrees)<\/label><input type=\"number\" id=\"bc-angle\" value=\"0\" min=\"0\" max=\"45\" step=\"1\"><\/div>\n<button class=\"calc-btn\" onclick=\"calcBearing()\">Calculate Bearing Frequencies<\/button>\n<\/div>\n<div class=\"results-panel\" id=\"bc-results\">\n<div class=\"result-grid\">\n<div class=\"result-card\"><div class=\"r-label\">BPFO \u2014 Outer Race<\/div><div class=\"r-value\" id=\"bc-bpfo\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">BPFI \u2014 Inner Race<\/div><div class=\"r-value\" id=\"bc-bpfi\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">BSF \u2014 Ball\/Roller Spin<\/div><div class=\"r-value\" id=\"bc-bsf\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">FTF \u2014 Cage (Train)<\/div><div class=\"r-value\" id=\"bc-ftf\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<\/div>\n<div style=\"margin-top:12px;font-size:12px;color:var(--text-muted);text-align:center;\">1\u00d7 shaft = <span id=\"bc-1x\">\u2014<\/span> Hz | BPFO\/BPFI ratio: <span id=\"bc-ratio\">\u2014<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n<div class=\"calc-panel\">\n<div class=\"calc-header\">\ud83d\udccf ISO 10816 Severity & RPM\u2194Hz & GMF<\/div>\n<div class=\"calc-body\">\n\n<div class=\"calc-form\">\n<div class=\"calc-row\">\n<div><label>Vibration Velocity (mm\/s RMS)<\/label><input type=\"number\" id=\"sev-vel\" value=\"4.5\" step=\"0.1\" min=\"0\"><\/div>\n<div><label>Machine Class<\/label><select id=\"sev-class\">\n<option value=\"1\">Class I \u2014 Small (\u2264 15 kW)<\/option>\n<option value=\"2\" selected>Class II \u2014 Medium (15\u201375 kW)<\/option>\n<option value=\"3\">Class III \u2014 Large, rigid foundation<\/option>\n<option value=\"4\">Class IV \u2014 Large, flexible foundation<\/option>\n<\/select><\/div>\n<\/div>\n<button class=\"calc-btn\" onclick=\"calcSeverity()\">Assess Severity<\/button>\n<\/div>\n<div class=\"severity-bar\"><div class=\"sev-zone sev-a\">A Good<\/div><div class=\"sev-zone sev-b\">B Acceptable<\/div><div class=\"sev-zone sev-c\">C Alert<\/div><div class=\"sev-zone sev-d\">D Danger<\/div><\/div>\n<div id=\"sev-result\" class=\"severity-result\" style=\"display:none;\"><\/div>\n\n<hr style=\"margin:20px 0;border:none;border-top:1px solid var(--border-light);\">\n\n<div style=\"font-weight:700;font-size:14px;color:var(--navy);margin-bottom:10px;\">\ud83d\udd04 RPM \u2194 Hz Converter<\/div>\n<div class=\"calc-form\">\n<div class=\"calc-row\">\n<div><label>RPM<\/label><input type=\"number\" id=\"conv-rpm\" value=\"1500\" min=\"0\" oninput=\"convRPM()\"><\/div>\n<div><label>Frequency (Hz)<\/label><input type=\"number\" id=\"conv-hz\" value=\"25\" step=\"0.01\" min=\"0\" oninput=\"convHz()\"><\/div>\n<\/div>\n<\/div>\n<div style=\"margin-top:8px;font-size:13px;color:var(--text-muted);text-align:center;\">1\u00d7 = <span id=\"conv-1x\">25.00<\/span> Hz | 2\u00d7 = <span id=\"conv-2x\">50.00<\/span> Hz | 3\u00d7 = <span id=\"conv-3x\">75.00<\/span> Hz | Period = <span id=\"conv-period\">40.00<\/span> ms<\/div>\n\n<hr style=\"margin:20px 0;border:none;border-top:1px solid var(--border-light);\">\n\n<div style=\"font-weight:700;font-size:14px;color:var(--navy);margin-bottom:10px;\">\u2699\ufe0f Gear Mesh Frequency (GMF)<\/div>\n<div class=\"calc-form\">\n<div class=\"calc-row\">\n<div><label>Shaft RPM (driving gear)<\/label><input type=\"number\" id=\"gmf-rpm\" value=\"1500\" min=\"1\"><\/div>\n<div><label>Number of Teeth (driving gear)<\/label><input type=\"number\" id=\"gmf-teeth1\" value=\"20\" min=\"1\"><\/div>\n<\/div>\n<div><label>Number of Teeth (driven gear) \u2014 optional, for gear ratio<\/label><input type=\"number\" id=\"gmf-teeth2\" value=\"60\" min=\"1\"><\/div>\n<button class=\"calc-btn\" onclick=\"calcGMF()\">Calculate GMF<\/button>\n<\/div>\n<div class=\"results-panel\" id=\"gmf-results\">\n<div class=\"result-grid\">\n<div class=\"result-card primary\"><div class=\"r-label\">Gear Mesh Frequency (GMF)<\/div><div class=\"r-value\" id=\"gmf-val\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">2\u00d7 GMF<\/div><div class=\"r-value\" id=\"gmf-2x\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">3\u00d7 GMF<\/div><div class=\"r-value\" id=\"gmf-3x\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">Gear Ratio<\/div><div class=\"r-value\" id=\"gmf-ratio\">\u2014<\/div><div class=\"r-unit\">:1<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">Driven Shaft Speed<\/div><div class=\"r-value\" id=\"gmf-driven\">\u2014<\/div><div class=\"r-unit\">RPM<\/div><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n<section class=\"section-bg alt\" id=\"fault-table\">\n<div class=\"container\">\n<div class=\"section-header\">\n<h2>Fault Identification at a Glance<\/h2>\n<p>Each mechanical fault produces a characteristic \"fingerprint\" in the vibration spectrum<\/p>\n<\/div>\n<div class=\"fault-grid\">\n<div class=\"fault-card f-unbal\"><div class=\"fc-icon\">\u2696\ufe0f<\/div><div class=\"fc-name\">Unbalance<\/div><div class=\"fc-freq unbal\">1\u00d7<\/div><div class=\"fc-desc\">Dominant peak at shaft speed. Radial. Amplitude \u221d speed\u00b2. Stable phase.<\/div><\/div>\n<div class=\"fault-card f-misal\"><div class=\"fc-icon\">\ud83d\udd27<\/div><div class=\"fc-name\">Misalignment<\/div><div class=\"fc-freq misal\">2\u00d7 (+ 1\u00d7, 3\u00d7)<\/div><div class=\"fc-desc\">Strong 2nd harmonic. High axial. 180\u00b0 phase across coupling.<\/div><\/div>\n<div class=\"fault-card f-loose\"><div class=\"fc-icon\">\ud83d\udd29<\/div><div class=\"fc-name\">Looseness<\/div><div class=\"fc-freq loose\">1\u00d7,2\u00d7,3\u00d7\u2026n\u00d7<\/div><div class=\"fc-desc\">\"Forest\" of harmonics. May show 0.5\u00d7 subharmonics.<\/div><\/div>\n<div class=\"fault-card f-bear\"><div class=\"fc-icon\">\ud83d\udd35<\/div><div class=\"fc-name\">Bearing Defect<\/div><div class=\"fc-freq bear\">BPFO\/BPFI\/BSF<\/div><div class=\"fc-desc\">Non-synchronous peaks. Sidebands at 1\u00d7. Noise floor rise.<\/div><\/div>\n<div class=\"fault-card f-gear\"><div class=\"fc-icon\">\u2699\ufe0f<\/div><div class=\"fc-name\">Gear Fault<\/div><div class=\"fc-freq gear\">GMF \u00b1 1\u00d7<\/div><div class=\"fc-desc\">Gear mesh frequency with sidebands at shaft speed.<\/div><\/div>\n<\/div>\n\n<div class=\"table-wrap\">\n<div class=\"table-title\">\ud83d\udcca Complete Diagnostic Reference Table<\/div><style id=\"vbm-diag-tablefix\">.table-scroll table td:first-child,.table-scroll table th:first-child{min-width:140px;word-break:normal;overflow-wrap:normal;hyphens:none}<\/style>\n<div class=\"table-scroll\"><table>\n<thead><tr><th>Fault<\/th><th>Primary Frequency<\/th><th>Harmonics<\/th><th>Direction<\/th><th>Phase Behaviour<\/th><th>Key Distinguishing Feature<\/th><\/tr><\/thead>\n<tbody>\n<tr><td><strong>Static unbalance<\/strong><\/td><td class=\"mono\">1\u00d7<\/td><td>Low \/ none<\/td><td>Radial (H,V)<\/td><td>In-phase both bearings<\/td><td>Pure 1\u00d7 sinusoid. Amplitude \u221d \u03c9\u00b2.<\/td><\/tr>\n<tr><td><strong>Dynamic unbalance<\/strong><\/td><td class=\"mono\">1\u00d7<\/td><td>Low \/ none<\/td><td>Radial (H,V)<\/td><td>~180\u00b0 between bearings<\/td><td>1\u00d7 dominant, bearings out of phase (couple).<\/td><\/tr>\n<tr><td><strong>Parallel misalignment<\/strong><\/td><td class=\"mono\">2\u00d7 (\u2265 1\u00d7)<\/td><td>1\u00d7, 3\u00d7<\/td><td>Radial<\/td><td>180\u00b0 across coupling<\/td><td>2\u00d7 often > 1\u00d7. High radial at coupling.<\/td><\/tr>\n<tr><td><strong>Angular misalignment<\/strong><\/td><td class=\"mono\">1\u00d7, 2\u00d7<\/td><td>3\u00d7<\/td><td>Axial dominant<\/td><td>180\u00b0 across coupling (axial)<\/td><td>High axial. Axial \u2265 50% of radial.<\/td><\/tr>\n<tr><td><strong>Component looseness<\/strong><\/td><td class=\"mono\">1\u00d7,2\u00d7\u202610\u00d7+<\/td><td>Many (~10\u00d7)<\/td><td>Radial<\/td><td>Erratic<\/td><td>\"Forest\" of harmonics. Possible 0.5\u00d7 sub.<\/td><\/tr>\n<tr><td><strong>Structural looseness<\/strong><\/td><td class=\"mono\">1\u00d7 or 2\u00d7<\/td><td>Few above 2\u00d7<\/td><td>Vertical<\/td><td>Unstable<\/td><td>Strong vertical. Responds to bolt check.<\/td><\/tr>\n<tr><td><strong>Outer race (BPFO)<\/strong><\/td><td class=\"mono\">BPFO, 2\u00d7BPFO\u2026<\/td><td>Multiple BPFO<\/td><td>Radial<\/td><td>N\/A<\/td><td>Non-synchronous. No 1\u00d7 sidebands.<\/td><\/tr>\n<tr><td><strong>Inner race (BPFI)<\/strong><\/td><td class=\"mono\">BPFI, 2\u00d7BPFI\u2026<\/td><td>Multiple BPFI<\/td><td>Radial<\/td><td>Modulated at 1\u00d7<\/td><td>BPFI harmonics with \u00b11\u00d7 sidebands.<\/td><\/tr>\n<tr><td><strong>Rolling element (BSF)<\/strong><\/td><td class=\"mono\">BSF, 2\u00d7BSF\u2026<\/td><td>Multiple BSF<\/td><td>Radial<\/td><td>N\/A<\/td><td>2\u00d7BSF often > 1\u00d7BSF. Non-synchronous.<\/td><\/tr>\n<tr><td><strong>Cage (FTF)<\/strong><\/td><td class=\"mono\">FTF \u2248 0.4\u00d7<\/td><td>2,3\u00d7 FTF<\/td><td>Radial<\/td><td>N\/A<\/td><td>Sub-synchronous (< 1\u00d7).<\/td><\/tr>\n<tr><td><strong>Gear mesh<\/strong><\/td><td class=\"mono\">GMF=N\u00d71\u00d7<\/td><td>2,3\u00d7 GMF<\/td><td>Radial+axial<\/td><td>Modulated at 1\u00d7<\/td><td>GMF with sidebands. N = teeth.<\/td><\/tr>\n<tr><td><strong>Electrical (motor)<\/strong><\/td><td class=\"mono\">2\u00d7 line freq<\/td><td>\u2014<\/td><td>Radial<\/td><td>Drops on power-off<\/td><td>100\/120 Hz. Instant drop test.<\/td><\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n<section class=\"section-bg white\" id=\"fft-demo\">\n<div class=\"container\">\n<div class=\"demo-panel\">\n<h3>Interactive FFT Spectrum Demonstration \u2014 16 Fault Scenarios<\/h3>\n<p style=\"text-align:center;color:var(--text-secondary);margin-bottom:20px;font-size:14px;\">Select a fault type to see characteristic time waveform and frequency spectrum. Compare patterns to identify the root cause.<\/p>\n\n<div class=\"demo-categories\">\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Baseline<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn active\" data-fault=\"normal\">\u2705 Normal<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Unbalance<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"unbal_static\">\u2696\ufe0f Static<\/button>\n<button class=\"demo-btn\" data-fault=\"unbal_dynamic\">\u2696\ufe0f Dynamic<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Misalignment<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"misal_parallel\">\ud83d\udd27 Parallel<\/button>\n<button class=\"demo-btn\" data-fault=\"misal_angular\">\ud83d\udd27 Angular<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Looseness<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"loose_component\">\ud83d\udd29 Component<\/button>\n<button class=\"demo-btn\" data-fault=\"loose_structural\">\ud83d\udd29 Structural<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Bearings<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"bear_outer\">\ud83d\udd35 BPFO<\/button>\n<button class=\"demo-btn\" data-fault=\"bear_inner\">\ud83d\udd35 BPFI<\/button>\n<button class=\"demo-btn\" data-fault=\"bear_rolling\">\ud83d\udd35 BSF<\/button>\n<button class=\"demo-btn\" data-fault=\"bear_cage\">\ud83d\udd35 FTF<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Gears<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"gear_healthy\">\u2699\ufe0f Healthy<\/button>\n<button class=\"demo-btn\" data-fault=\"gear_worn\">\u2699\ufe0f Worn<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Other<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"electrical\">\u26a1 Electrical<\/button>\n<button class=\"demo-btn\" data-fault=\"belt\">\ud83d\udd17 Belt<\/button>\n<button class=\"demo-btn\" data-fault=\"cavitation\">\ud83d\udca7 Cavitation<\/button>\n<button class=\"demo-btn\" data-fault=\"oilwhirl\">\ud83c\udf00 Oil Whirl<\/button>\n<\/div>\n<\/div>\n\n<\/div>\n\n<div class=\"demo-desc\" id=\"demo-desc\">Normal operating condition \u2014 low, stable vibration. Small 1\u00d7 peak from residual unbalance. Clean spectrum.<\/div>\n<div class=\"demo-charts\">\n<div class=\"chart-box\"><h4>Time Domain (Waveform)<\/h4><canvas id=\"demo-time\"><\/canvas><\/div>\n<div class=\"chart-box\"><h4>Frequency Spectrum (FFT)<\/h4><canvas id=\"demo-fft\"><\/canvas><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n<main class=\"main-content\" id=\"fundamentals\">\n<div class=\"container\">\n<div class=\"content-layout\">\n<article class=\"article-content\">\n\n<h2>What is Vibration Analysis?<\/h2>\n<div class=\"info-box\" style=\"border-left-color:var(--navy);background:var(--beige-light);\">\n<div class=\"box-title\" style=\"font-size:16px;\">Quick Answer<\/div>\n<p style=\"font-size:15px;\"><strong>Vibration analysis<\/strong> is the process of measuring and interpreting mechanical oscillations of rotating machinery to diagnose faults without disassembly. Using <strong>FFT<\/strong> (Fast Fourier Transform), the complex vibration signal is decomposed into individual frequency components. Each fault produces a characteristic spectral \"fingerprint\": <a href=\"https:\/\/vibromera.eu\/glossary\/unbalance\/\">unbalance<\/a> at 1\u00d7 RPM, <a href=\"https:\/\/vibromera.eu\/glossary\/misalignment\/\">misalignment<\/a> at 2\u00d7, looseness as multiple harmonics, bearing defects at non-synchronous frequencies. The <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\">Balanset-1A<\/a> performs both balancing and spectrum analysis in one portable instrument.<\/p>\n<\/div>\n<p>Every rotating machine vibrates. In a healthy machine, vibration is low and stable \u2014 its normal \"operating signature.\" As defects develop, vibration changes in predictable ways. By measuring and analysing these changes, we can identify the root cause, predict failure, and schedule maintenance before catastrophic breakdown. This is the foundation of <strong>predictive maintenance<\/strong>.<\/p>\n\n<h2>FFT: The Core of Spectrum Analysis<\/h2>\n<p>A vibration sensor (accelerometer) converts mechanical oscillation into an electrical signal. Displayed over time, this is the <strong>waveform<\/strong> \u2014 a complex, seemingly chaotic curve when multiple faults are present. FFT (Fast Fourier Transform) decomposes this complex signal into individual sinusoidal components, each with its own frequency and amplitude.<\/p>\n<p>Think of FFT as a prism splitting white light into a rainbow. The complex waveform is \"white light\" \u2014 FFT reveals the individual \"colours\" (frequencies) hidden inside. The result is the <strong>vibration spectrum<\/strong> \u2014 the primary diagnostic tool.<\/p>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Rotational Frequency<\/div>\n<div class=\"formula-main\">f\u2081\u2093 = RPM \/ 60 (Hz)<\/div>\n<div class=\"formula-note\">1\u00d7 = shaft rotational frequency \u2014 the reference for all spectral analysis<\/div>\n<\/div>\n\n<h3>Key Spectrum Parameters<\/h3>\n<ul>\n<li><strong>Frequency (X-axis, Hz):<\/strong> How often oscillations occur. Directly linked to the source. 1\u00d7 = shaft speed. 2\u00d7 = twice shaft speed.<\/li>\n<li><strong>Amplitude (Y-axis, mm\/s RMS):<\/strong> Vibration intensity at each frequency. Higher peaks = more energy = more serious condition.<\/li>\n<li><strong>Harmonics:<\/strong> Integer multiples of the fundamental: 2\u00d7 (2nd), 3\u00d7 (3rd), 4\u00d7, etc. Their presence and relative height carry diagnostic information.<\/li>\n<li><strong>Phase (\u00b0):<\/strong> Timing relationship at different measurement points. Essential for distinguishing unbalance (in-phase) from misalignment (180\u00b0).<\/li>\n<\/ul>\n\n\n<h2 id=\"units\">Vibration Measurement Units: Displacement, Velocity, Acceleration<\/h2>\n<p>Vibration can be measured as three different physical parameters. Each emphasises different frequency ranges, making them suited to different diagnostic tasks. Understanding when to use which parameter is fundamental to effective analysis.<\/p>\n\n<div class=\"units-grid\">\n<div class=\"unit-card disp\">\n<h4>\ud83d\udccf Displacement<\/h4>\n<div class=\"u-param\">\u00b5m (peak-to-peak) or mil<\/div>\n<div class=\"u-range\">Best range: <strong>1\u2013100 Hz<\/strong><\/div>\n<p>Measures how <em>far<\/em> the surface moves. Emphasises low frequencies \u2014 ideal for slow-speed machines, shaft orbit analysis, and proximity probes on journal bearings. 1 mil = 25.4 \u00b5m.<\/p>\n<\/div>\n<div class=\"unit-card vel\">\n<h4>\ud83d\udcc8 Velocity<\/h4>\n<div class=\"u-param\">mm\/s (RMS)<\/div>\n<div class=\"u-range\">Best range: <strong>10\u20131000 Hz<\/strong><\/div>\n<p>Measures how <em>fast<\/em> the surface moves. The <strong>standard parameter<\/strong> for general machinery monitoring per ISO 10816. Flat frequency response gives equal weight to most fault types. <strong>Balanset-1A measures in mm\/s RMS.<\/strong><\/p>\n<\/div>\n<div class=\"unit-card acc\">\n<h4>\ud83d\udca5 Acceleration<\/h4>\n<div class=\"u-param\">m\/s\u00b2 or g (RMS\/peak)<\/div>\n<div class=\"u-range\">Best range: <strong>500 Hz \u2013 20 kHz+<\/strong><\/div>\n<p>Measures the <em>force<\/em> of vibration. Emphasises high frequencies \u2014 ideal for early bearing defects, gear mesh, and impacts. 1 g = 9.81 m\/s\u00b2. Used for envelope\/demodulation analysis.<\/p>\n<\/div>\n<\/div>\n\n<div class=\"table-wrap\">\n<div class=\"table-title\">When to Use Each Parameter<\/div>\n<div class=\"table-scroll\"><table>\n<thead><tr><th>Parameter<\/th><th>Unit<\/th><th>Frequency Range<\/th><th>Best For<\/th><th>Standards<\/th><\/tr><\/thead>\n<tbody>\n<tr><td><strong>Displacement<\/strong><\/td><td class=\"mono\">\u00b5m pk-pk<\/td><td>1\u2013100 Hz<\/td><td>Slow machines (< 600 RPM), shaft orbit, proximity probes, journal bearings<\/td><td>ISO 7919 (shaft vibration)<\/td><\/tr>\n<tr><td><strong>Velocity<\/strong><\/td><td class=\"mono\">mm\/s RMS<\/td><td>10\u20131000 Hz<\/td><td><strong>General machinery monitoring<\/strong> \u2014 unbalance, misalignment, looseness. Default parameter.<\/td><td>ISO 10816, ISO 20816<\/td><\/tr>\n<tr><td><strong>Acceleration<\/strong><\/td><td class=\"mono\">g or m\/s\u00b2 RMS<\/td><td>500 Hz \u2013 20 kHz<\/td><td>Early bearing defects, gear mesh, impacts, high-speed machinery<\/td><td>ISO 15242 (bearing vibration)<\/td><\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Conversion at a Single Frequency<\/div>\n<div class=\"formula-main\" style=\"font-size:16px;\">v = 2\u03c0f \u00b7 d | a = 2\u03c0f \u00b7 v = (2\u03c0f)\u00b2 \u00b7 d<\/div>\n<div class=\"formula-note\">d = displacement (m), v = velocity (m\/s), a = acceleration (m\/s\u00b2), f = frequency (Hz)<\/div>\n<\/div>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udca1 Rule of Thumb<\/div>\n<p>If you have only one sensor and one parameter to choose \u2014 <strong>choose velocity (mm\/s RMS)<\/strong>. It covers the broadest range of common faults with flat response. The Balanset-1A uses this as its native parameter. Add acceleration measurement only when you need to catch early-stage bearing or gear defects at high frequencies.<\/p>\n<\/div>\n\n<h2 id=\"measurement\">Measurement Technique with Balanset-1A<\/h2>\n<h3>Sensor Placement<\/h3>\n<p>The quality of diagnosis depends entirely on measurement quality. Vibration forces are transmitted through bearings, so sensors must be mounted on bearing housings \u2014 as close to the bearing as possible, on the load-bearing structure (not covers or cooling fins).<\/p>\n<ul>\n<li><strong>Surface preparation:<\/strong> Clean, flat, free of paint flakes. Magnetic base must sit flush.<\/li>\n<li><strong>Radial horizontal (H):<\/strong> Perpendicular to shaft, horizontal plane. Often highest amplitude.<\/li>\n<li><strong>Radial vertical (V):<\/strong> Perpendicular to shaft, vertical plane.<\/li>\n<li><strong>Axial (A):<\/strong> Parallel to shaft. Critical for detecting misalignment.<\/li>\n<\/ul>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udca1 Two-Channel Diagnostic Trick<\/div>\n<p>The Balanset-1A has 2 channels. For diagnostics, mount both sensors on the <em>same<\/em> bearing \u2014 one radial, one axial. This gives simultaneous radial + axial spectrums, enabling instant misalignment detection.<\/p>\n<\/div>\n\n<h3>Balanset-1A Modes for Diagnostics<\/h3>\n<ul>\n<li><strong>F1 \u2014 Spectrum Analyser:<\/strong> Full FFT display. The primary diagnostic mode.<\/li>\n<li><strong>F5 \u2014 Vibrometer:<\/strong> Quick assessment. Compare V1s (total RMS) vs. V1o (1\u00d7). If V1s \u2248 V1o \u2192 unbalance. If V1s \u226b V1o \u2192 other faults.<\/li>\n<li><strong>F8 \u2014 Charts:<\/strong> Detailed spectrum + time waveform. Best for harmonic patterns and bearing frequencies.<\/li>\n<\/ul>\n\n<div class=\"info-box warning\">\n<div class=\"box-title\">\u26a0\ufe0f V1s vs. V1o \u2014 The First Diagnostic Check<\/div>\n<p>Before balancing, compare V1s with V1o. If V1s \u226b V1o (e.g., 8 vs. 2 mm\/s), most vibration is NOT from unbalance. Balancing won't solve it \u2014 examine the full spectrum.<\/p>\n<\/div>\n\n\n<h2 id=\"phase\">Phase Analysis \u2014 The Diagnostic Differentiator<\/h2>\n<p>Frequency tells you <em>what<\/em> is vibrating; phase tells you <em>how<\/em>. Two faults can produce identical spectrums (both dominated by 1\u00d7) \u2014 only phase analysis distinguishes them. Phase is the angular relationship between vibration at different measurement points, measured in degrees (0\u00b0\u2013360\u00b0).<\/p>\n\n<div class=\"table-wrap\">\n<div class=\"table-title\">\ud83e\udded Phase \u2192 Diagnosis Reference Table<\/div>\n<div class=\"table-scroll\"><table>\n<thead><tr><th>Phase Relationship<\/th><th>Measurement Points<\/th><th>Diagnosis<\/th><th>Explanation<\/th><\/tr><\/thead>\n<tbody>\n<tr><td class=\"mono\"><strong>0\u00b0 (in-phase)<\/strong><\/td><td>Bearing 1 \u2194 Bearing 2 (radial)<\/td><td><strong>Static unbalance<\/strong><\/td><td>Both bearings move together in sync \u2014 single heavy spot in centre of rotor. Single-plane correction.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~180\u00b0 (anti-phase)<\/strong><\/td><td>Bearing 1 \u2194 Bearing 2 (radial)<\/td><td><strong>Dynamic (couple) unbalance<\/strong><\/td><td>Bearings rock in opposition \u2014 two heavy spots at different planes create a rocking couple. Two-plane correction needed.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~90\u00b0<\/strong><\/td><td>Horizontal \u2194 Vertical (same bearing)<\/td><td><strong>Unbalance (any type)<\/strong><\/td><td>Normal for unbalance \u2014 force vector rotates with shaft, producing ~90\u00b0 between H and V at same point.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~180\u00b0<\/strong><\/td><td>Across coupling (radial)<\/td><td><strong>Parallel misalignment<\/strong><\/td><td>Coupling forces push shafts apart in opposite radial directions. 180\u00b0 across coupling with high 2\u00d7 is the signature.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~180\u00b0<\/strong><\/td><td>Across coupling (axial)<\/td><td><strong>Angular misalignment<\/strong><\/td><td>Shafts alternately push\/pull axially. 180\u00b0 axial across coupling with high 1\u00d7 and 2\u00d7 is definitive.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>0\u00b0<\/strong><\/td><td>Across coupling (axial)<\/td><td><strong>Not misalignment<\/strong><\/td><td>Both sides moving same axial direction \u2014 likely thermal growth, piping strain, or soft foot. Not angular misalignment.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>Erratic \/ unstable<\/strong><\/td><td>Any consistent points<\/td><td><strong>Mechanical looseness<\/strong><\/td><td>Phase readings jump randomly between measurements \u2014 characteristic of impacts in loose joints. Unstable phase = looseness.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>Slowly drifting<\/strong><\/td><td>Any point, over time<\/td><td><strong>Resonance or thermal effects<\/strong><\/td><td>Gradual phase shift during warmup suggests structural stiffness changing with temperature (thermal misalignment).<\/td><\/tr>\n<tr><td class=\"mono\"><strong>Consistent, non-0\/180\u00b0<\/strong><\/td><td>Bearing 1 \u2194 Bearing 2<\/td><td><strong>Combined static + couple unbalance<\/strong><\/td><td>Phase between 0\u00b0 and 180\u00b0 indicates a mix of static and couple components \u2014 requires two-plane balancing.<\/td><\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udca1 Phase Measurement with Balanset-1A<\/div>\n<p>The Balanset-1A displays phase at 1\u00d7 (the F1 value in vibrometer mode) using the tachometer as reference. To compare phase between two bearings, measure each bearing in the same direction (e.g., horizontal) with the tachometer on the same reference mark. The difference in phase readings reveals the fault type. No special software needed \u2014 just subtract the two readings.<\/p>\n<\/div>\n\n\n<h2 id=\"unbalance\">Fault 1: Unbalance<\/h2>\n<p><strong>Cause:<\/strong> Centre of mass displaced from rotation axis. Manufacturing tolerances, deposit buildup, erosion, broken blade, lost weight.<\/p>\n<p><strong>Spectrum:<\/strong> Dominant peak at exactly 1\u00d7 RPM. Very low harmonics. Radial vibration. Amplitude increases with speed\u00b2 (quadratic). Phase is stable and repeatable.<\/p>\n\n<h4>Static Unbalance (Single-Plane)<\/h4>\n<p>Pure 1\u00d7 peak, sinusoidal waveform. Both bearings in-phase. Single-plane correction.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-unbal-static\"><\/canvas><\/div>\n<div class=\"chart-caption\">Static unbalance \u2014 dominant 1\u00d7 at 25 Hz (1500 RPM). Minimal harmonics.<\/div>\n\n<h4>Dynamic Unbalance (Two-Plane \/ Couple)<\/h4>\n<p>Also 1\u00d7 dominant, but bearings ~180\u00b0 out of phase. Two-plane correction required.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-unbal-dynamic\"><\/canvas><\/div>\n<div class=\"chart-caption\">Dynamic unbalance \u2014 1\u00d7 dominant. Spectrum similar to static but phase differs at bearings.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Perform <a href=\"https:\/\/vibromera.eu\/glossary\/balancing\/\">rotor balancing<\/a> with the Balanset-1A. G-grade tolerance per <a href=\"https:\/\/vibromera.eu\/glossary\/iso-1940-1\/\">ISO 1940-1<\/a>.<\/p><\/div>\n\n<h2 id=\"misalignment\">Fault 2: Shaft Misalignment<\/h2>\n<p><strong>Cause:<\/strong> Axes of coupled shafts do not coincide. Can be parallel (offset) or angular (tilted), usually both.<\/p>\n\n<h4>Parallel Misalignment (Radial)<\/h4>\n<p>High 1\u00d7 and 2\u00d7 in the radial direction. 2\u00d7 often \u2265 1\u00d7. 180\u00b0 phase shift across coupling.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-misal-parallel\"><\/canvas><\/div>\n<div class=\"chart-caption\">Parallel misalignment \u2014 radial direction. Strong 1\u00d7 and 2\u00d7 with minor 3\u00d7.<\/div>\n\n<h4>Angular Misalignment \u2014 Radial<\/h4>\n<p>1\u00d7 and 2\u00d7 present in radial, but 2\u00d7 typically dominates.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-misal-angular-r\"><\/canvas><\/div>\n<div class=\"chart-caption\">Angular misalignment \u2014 radial (R). 2\u00d7 > 1\u00d7.<\/div>\n\n<h4>Angular Misalignment \u2014 Axial<\/h4>\n<p>Axial vibration \u2265 50% of radial. 180\u00b0 phase across coupling in axial. This is the key distinguishing measurement.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-misal-angular-a\"><\/canvas><\/div>\n<div class=\"chart-caption\">Angular misalignment \u2014 axial (A). Very high 2\u00d7 in axial direction.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Balancing will NOT help. Stop the machine and perform shaft alignment. Re-check vibration after.<\/p><\/div>\n\n<h2 id=\"looseness\">Fault 3: Mechanical Looseness<\/h2>\n<p><strong>Cause:<\/strong> Loss of structural stiffness \u2014 loose bolts, cracks in foundation, worn bearing seats, excessive clearances.<\/p>\n\n<h4>Component Looseness<\/h4>\n<p>\"Forest\" of harmonics \u2014 1\u00d7, 2\u00d7, 3\u00d7, 4\u00d7\u2026 up to 10\u00d7+ with decreasing amplitude. May show 0.5\u00d7 subharmonics.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-loose-component\"><\/canvas><\/div>\n<div class=\"chart-caption\">Component looseness \u2014 many harmonics 1\u00d7 through 10\u00d7. Note 0.5\u00d7 subharmonic.<\/div>\n\n<h4>Structural Looseness<\/h4>\n<p>1\u00d7 and\/or 2\u00d7 dominant. Few higher harmonics. Strong vertical vibration.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-loose-structural\"><\/canvas><\/div>\n<div class=\"chart-caption\">Structural looseness \u2014 1\u00d7 and 2\u00d7 dominate. Minimal higher harmonics.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Inspect and tighten mounting bolts. Check foundation. Always check looseness <em>before<\/em> balancing.<\/p><\/div>\n\n<h2 id=\"bearings\">Fault 4: Rolling Bearing Defects<\/h2>\n<p><strong>Cause:<\/strong> Pitting, spalling, wear on raceways, rolling elements, or cage.<\/p>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Bearing Defect Frequencies<\/div>\n<div class=\"formula-main\" style=\"font-size:16px;line-height:2;\">\nBPFO = (n\/2)(1 \u2212 Bd\/Pd\u00b7cos \u03b1) \u00b7 f<sub>s<\/sub><br>\nBPFI = (n\/2)(1 + Bd\/Pd\u00b7cos \u03b1) \u00b7 f<sub>s<\/sub><br>\nBSF = (Pd\/2Bd)(1 \u2212 (Bd\/Pd\u00b7cos \u03b1)\u00b2) \u00b7 f<sub>s<\/sub><br>\nFTF = \u00bd(1 \u2212 Bd\/Pd\u00b7cos \u03b1) \u00b7 f<sub>s<\/sub>\n<\/div>\n<div class=\"formula-note\">n = rolling elements | Bd = ball dia | Pd = pitch dia | \u03b1 = contact angle | f<sub>s<\/sub> = RPM\/60<\/div>\n<\/div>\n\n<h4>Outer Race Defect (BPFO)<\/h4>\n<p>Series of peaks at BPFO, 2\u00d7BPFO, 3\u00d7BPFO\u2026 No 1\u00d7 sidebands (stationary ring). Most common bearing fault.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-outer\"><\/canvas><\/div>\n<div class=\"chart-caption\">Outer race defect \u2014 BPFO harmonics at non-synchronous frequencies. No sidebands.<\/div>\n\n<h4>Inner Race Defect (BPFI)<\/h4>\n<p>BPFI harmonics with \u00b11\u00d7 sidebands (rotating ring, load zone modulation). Sideband pattern is the key identifier.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-inner\"><\/canvas><\/div>\n<div class=\"chart-caption\">Inner race defect \u2014 BPFI harmonics with \u00b11\u00d7 sidebands (smaller peaks flanking main peaks).<\/div>\n\n<h4>Rolling Element Defect (BSF)<\/h4>\n<p>BSF harmonics. 2\u00d7BSF often dominant. Non-synchronous. Often accompanied by race damage.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-rolling\"><\/canvas><\/div>\n<div class=\"chart-caption\">Rolling element defect \u2014 BSF harmonics. Note 2\u00d7BSF is highest (two-element damage).<\/div>\n\n<h4>Cage Defect (FTF)<\/h4>\n<p>Sub-synchronous peaks (FTF \u2248 0.4\u00d7 shaft speed). Low frequency. Often accompanies other bearing damage.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-cage\"><\/canvas><\/div>\n<div class=\"chart-caption\">Cage defect \u2014 FTF and harmonics below 1\u00d7 shaft speed (sub-synchronous).<\/div>\n\n<div class=\"info-box success\">\n<div class=\"box-title\">Bearing Defect Progression (4 Stages)<\/div>\n<p><strong>Stage 1 \u2014 Subsurface:<\/strong> Ultrasonic zone (> 5 kHz). Not visible on standard FFT. Detectable by spike energy \/ enveloping.<\/p>\n<p><strong>Stage 2 \u2014 Early defect:<\/strong> Bearing frequencies appear (BPFO, BPFI). Low amplitude. This is where Balanset-1A begins detection.<\/p>\n<p><strong>Stage 3 \u2014 Progressed:<\/strong> Multiple harmonics. Sidebands develop. Noise floor rises.<\/p>\n<p><strong>Stage 4 \u2014 Advanced:<\/strong> Broadband noise. Bearing frequencies may disappear into noise. Replacement urgent.<\/p>\n<\/div>\n\n\n<h3 id=\"envelope\">Envelope (Demodulation) Analysis \u2014 Early Bearing Detection<\/h3>\n<p>Standard FFT spectrum analysis detects bearing defects from Stage 2 onward. But in Stage 1, bearing impacts are too weak to appear above the noise floor. <strong>Envelope analysis<\/strong> (also called demodulation or high-frequency detection, HFD) extends detection to much earlier stages.<\/p>\n\n<h4>How It Works<\/h4>\n<p>When a rolling element hits a defect, it generates a short impact pulse that excites high-frequency structural resonances (typically 5\u201320 kHz). These resonances \"ring\" briefly at each impact. Envelope analysis works in three steps:<\/p>\n<ol>\n<li><strong>Band-pass filter:<\/strong> Isolate the high-frequency resonance band (e.g., 5\u201315 kHz) where the impacts ring.<\/li>\n<li><strong>Rectify and envelope:<\/strong> Extract the amplitude modulation pattern \u2014 the \"envelope\" that follows the peaks of the ringing.<\/li>\n<li><strong>FFT of the envelope:<\/strong> Apply FFT to the envelope signal. The result shows the <em>repetition rate<\/em> of impacts \u2014 which equals the bearing defect frequencies (BPFO, BPFI, BSF, FTF).<\/li>\n<\/ol>\n\n<div class=\"info-box\">\n<div class=\"box-title\">Why Envelope Detects Earlier<\/div>\n<p>In the raw spectrum, a weak impact at BPFO might produce 0.1 mm\/s \u2014 invisible among machine noise of 2 mm\/s. But that same impact excites a resonance at 8 kHz where there is no other vibration source. After demodulation, the BPFO repetition pattern emerges clearly from a clean background.<\/p>\n<\/div>\n\n<h4>Related Parameters<\/h4>\n<ul>\n<li><strong>Spike Energy (SE):<\/strong> Overall measurement of high-frequency impact energy. Scalar trending value. Good for \"go\/no-go\" screening.<\/li>\n<li><strong>gSE \/ HFD \/ PeakVue:<\/strong> Vendor-specific names for envelope-derived parameters. All based on the same principle.<\/li>\n<li><strong>Acceleration enveloping:<\/strong> The Balanset-1A measures in velocity (mm\/s). For full envelope analysis, a dedicated analyser with acceleration input and band-pass filtering capability is ideal. However, the Balanset-1A's FFT can still detect Stage 2+ bearing defects effectively in the standard velocity spectrum.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-envelope\"><\/canvas><\/div>\n<div class=\"chart-caption\">Envelope spectrum of inner race defect \u2014 BPFI harmonics emerge clearly from demodulated high-frequency signal. Compare with raw velocity spectrum where these may be hidden in noise.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Check lubrication. Plan bearing replacement. Increase monitoring frequency.<\/p><\/div>\n\n<h2 id=\"gears\">Fault 5: Gear Defects<\/h2>\n<p><strong>Cause:<\/strong> Worn, pitted, or broken teeth. Gear eccentricity. GMF = number of teeth \u00d7 shaft RPM \/ 60.<\/p>\n\n<h4>Gear Eccentricity<\/h4>\n<p>GMF with sidebands at \u00b11\u00d7 shaft speed. Gear's 1\u00d7 may also be elevated.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-gear-eccentric\"><\/canvas><\/div>\n<div class=\"chart-caption\">Gear eccentricity \u2014 GMF at 500 Hz with \u00b11\u00d7 sidebands. Elevated 1\u00d7.<\/div>\n\n<h4>Gear Tooth Wear \/ Damage<\/h4>\n<p>Multiple GMF harmonics with dense sidebands. Severity tracks with sideband count and amplitude.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-gear-wear\"><\/canvas><\/div>\n<div class=\"chart-caption\">Gear wear \u2014 GMF and 2\u00d7GMF with multiple sidebands at 1\u00d7 intervals.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Check gearbox oil for metallic particles. Schedule inspection. Monitor GMF sideband trend.<\/p><\/div>\n\n<h2 id=\"electrical\">Electrical Faults (Motors)<\/h2>\n<p>Electromagnetic faults produce vibration at <strong>2\u00d7 line frequency<\/strong> (100 Hz on 50 Hz grids, 120 Hz on 60 Hz). Critical test: vibration disappears <em>instantly<\/em> when power is cut. Mechanical faults decay gradually.<\/p>\n<ul>\n<li><strong>Stator eccentricity:<\/strong> 2\u00d7 line frequency, steady amplitude.<\/li>\n<li><strong>Rotor bar defects:<\/strong> Sidebands around line frequency at slip frequency intervals.<\/li>\n<li><strong>Soft foot:<\/strong> Vibration changes when individual motor feet are loosened.<\/li>\n<\/ul>\n\n\n<h2 id=\"belt\">Fault 7: Belt Drive Problems<\/h2>\n<p><strong>Cause:<\/strong> Worn, misaligned, or improperly tensioned belts. Belt drives generate vibration at the <strong>belt pass frequency<\/strong>, which is typically a sub-synchronous frequency (below 1\u00d7 shaft speed) since the belt is longer than the pulley circumference.<\/p>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Belt Frequency<\/div>\n<div class=\"formula-main\" style=\"font-size:16px;\">f<sub>belt<\/sub> = (\u03c0 \u00b7 D \u00b7 RPM) \/ (60 \u00b7 L)<\/div>\n<div class=\"formula-note\">D = pulley diameter (m) | L = belt length (m) | RPM = pulley speed<br>Simplified: f<sub>belt<\/sub> = pulley circumference speed \/ belt length<\/div>\n<\/div>\n\n<h4>Common Belt Signatures<\/h4>\n<ul>\n<li><strong>Belt wear \/ defect:<\/strong> Peaks at belt frequency (f<sub>belt<\/sub>) and its harmonics (2\u00d7, 3\u00d7, 4\u00d7 f<sub>belt<\/sub>). These appear below 1\u00d7 shaft speed \u2014 sub-synchronous peaks are the key indicator.<\/li>\n<li><strong>Belt misalignment:<\/strong> Elevated axial vibration at 1\u00d7 and 2\u00d7 shaft speed. Similar to shaft misalignment but restricted to the belt-driven machine.<\/li>\n<li><strong>Improper tension:<\/strong> High 1\u00d7 vibration that changes dramatically with belt tension adjustment. Overtight belts increase bearing load; loose belts cause slapping and belt-frequency peaks.<\/li>\n<li><strong>Resonance:<\/strong> Belt natural frequency (belt \"flutter\") can be excited if belt span resonance coincides with operating speed. Visible as broad peak at belt natural frequency.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-belt\"><\/canvas><\/div>\n<div class=\"chart-caption\">Belt drive defect \u2014 sub-synchronous peaks at belt frequency and harmonics (below 1\u00d7 shaft speed at 25 Hz).<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Check belt condition, tension, and pulley alignment. Replace worn belts. For recurring issues, verify pulley alignment with a laser tool or straight-edge.<\/p><\/div>\n\n\n<h2 id=\"cavitation\">Fault 8: Pump Cavitation<\/h2>\n<p><strong>Cause:<\/strong> Vapor bubbles form and collapse violently when local pressure drops below the liquid's vapor pressure \u2014 typically at the pump suction. Each bubble collapse creates a micro-impact. Thousands of collapses per second generate a characteristic broadband noise.<\/p>\n\n<h4>Spectral Signature<\/h4>\n<ul>\n<li><strong>Broadband high-frequency energy:<\/strong> Unlike mechanical faults (which produce discrete peaks), cavitation generates a raised noise floor across a wide frequency range, typically above 2\u20135 kHz. The spectrum looks like a \"hump\" or elevated plateau rather than sharp peaks.<\/li>\n<li><strong>Random, non-periodic:<\/strong> No harmonics, no relationship to shaft speed. The noise sounds like \"gravel\" or \"crackling\" \u2014 audible even without instruments.<\/li>\n<li><strong>Low-frequency effects:<\/strong> Severe cavitation may also cause instability at 1\u00d7 and broadband low-frequency noise from flow turbulence.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-cavitation\"><\/canvas><\/div>\n<div class=\"chart-caption\">Pump cavitation \u2014 broadband high-frequency noise (raised floor above 200 Hz). No discrete peaks \u2014 contrast with bearing defects which show specific frequencies.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Increase suction pressure (lower pump, open suction valve, reduce suction pipe losses). Check NPSH<sub>available<\/sub> vs. NPSH<sub>required<\/sub>. Reduce pump speed if possible. Cavitation causes rapid erosion damage \u2014 do not ignore.<\/p><\/div>\n\n\n<h2 id=\"oilwhirl\">Fault 9: Oil Whirl & Oil Whip (Journal Bearings)<\/h2>\n<p><strong>Cause:<\/strong> Fluid-film instability in journal (sleeve) bearings. The oil film wedge forces the shaft to orbit within the bearing clearance at a sub-synchronous frequency. This is distinct from rolling element bearing defects and occurs only in plain\/journal bearings.<\/p>\n\n<h4>Oil Whirl<\/h4>\n<ul>\n<li><strong>Frequency:<\/strong> Approximately <strong>0.42\u00d7 to 0.48\u00d7<\/strong> shaft speed (often cited as ~0.43\u00d7). This is a sub-synchronous peak that tracks shaft speed \u2014 if RPM increases, the whirl frequency increases proportionally.<\/li>\n<li><strong>Spectrum:<\/strong> A single peak at ~0.43\u00d7 that shifts with speed. Amplitude may be moderate.<\/li>\n<li><strong>Condition:<\/strong> Precursor to oil whip. Usually not immediately destructive but indicates instability.<\/li>\n<\/ul>\n\n<h4>Oil Whip<\/h4>\n<ul>\n<li><strong>Frequency:<\/strong> Locks onto the rotor's first <a href=\"https:\/\/vibromera.eu\/glossary\/natural-frequency\/\">natural frequency<\/a> (critical speed). Unlike whirl, it does NOT track shaft speed \u2014 the frequency remains constant as RPM changes.<\/li>\n<li><strong>Spectrum:<\/strong> Large sub-synchronous peak at the rotor's first critical speed. Amplitude can be very high \u2014 destructive.<\/li>\n<li><strong>Condition:<\/strong> <strong>Dangerous.<\/strong> Immediate action required. Can lead to bearing wipe-out and shaft damage.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-oilwhirl\"><\/canvas><\/div>\n<div class=\"chart-caption\">Oil whirl \u2014 sub-synchronous peak at ~0.43\u00d7 shaft speed (\u2248 10.7 Hz for 1500 RPM). Distinct from 0.5\u00d7 looseness.<\/div>\n\n<div class=\"info-box warning\">\n<div class=\"box-title\">\u26a0\ufe0f Oil Whirl vs. Looseness \u2014 How to Distinguish<\/div>\n<p>Both produce sub-synchronous peaks, but: <strong>Oil whirl<\/strong> is at ~0.43\u00d7 (not exactly 0.5\u00d7) and tracks with speed. <strong>Looseness<\/strong> produces peaks at exactly 0.5\u00d7, 1.5\u00d7, 2.5\u00d7 and does not track with speed (stays at fixed fractions of 1\u00d7). Oil whirl only occurs in journal\/sleeve bearings \u2014 if the machine has rolling element bearings, it cannot be oil whirl.<\/p>\n<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> For oil whirl: check bearing clearance, oil viscosity, and load. Increase bearing loading or change oil viscosity. For oil whip: <strong>reduce speed immediately<\/strong> below the critical threshold. Consult a rotor dynamics specialist.<\/p><\/div>\n\n\n<h2 id=\"iso-full\">ISO 10816 Vibration Severity \u2014 Complete Classification Table<\/h2>\n<p>ISO 10816 (superseded by ISO 20816 but still widely referenced) defines vibration severity zones for four machine classes. Vibration is measured as velocity in mm\/s RMS on bearing housings. The table below shows all zone boundaries for all four classes \u2014 use it as a quick reference when evaluating measurements.<\/p>\n\n<div class=\"table-wrap\" style=\"overflow:visible;\">\n<div class=\"table-title\">\ud83d\udccb ISO 10816-3 Vibration Severity Zones \u2014 All Machine Classes (mm\/s RMS)<\/div>\n<div class=\"table-scroll\"><table style=\"text-align:center;\">\n<thead><tr>\n<th style=\"text-align:left;min-width:180px;\">Machine Class<\/th>\n<th style=\"background:#16a34a;color:#fff;min-width:100px;\">Zone A<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Good<\/span><\/th>\n<th style=\"background:#65a30d;color:#fff;min-width:100px;\">Zone B<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Acceptable<\/span><\/th>\n<th style=\"background:#d97706;color:#fff;min-width:100px;\">Zone C<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Alert<\/span><\/th>\n<th style=\"background:#dc2626;color:#fff;min-width:100px;\">Zone D<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Danger<\/span><\/th>\n<\/tr><\/thead>\n<tbody>\n<tr style=\"background:#f0fdf4;\">\n<td style=\"text-align:left;\"><strong>Class I<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Small machines \u2264 15 kW<br>(pumps, fans, compressors)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 0.71<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">0.71 \u2013 1.8<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">1.8 \u2013 4.5<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 4.5<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align:left;\"><strong>Class II<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Medium machines 15\u201375 kW<br>(without special foundation)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 1.8<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">1.8 \u2013 4.5<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">4.5 \u2013 11.2<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 11.2<\/td>\n<\/tr>\n<tr style=\"background:#f0fdf4;\">\n<td style=\"text-align:left;\"><strong>Class III<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Large machines > 75 kW<br>(rigid foundation)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 2.8<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">2.8 \u2013 7.1<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">7.1 \u2013 18<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 18<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align:left;\"><strong>Class IV<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Large machines > 75 kW<br>(flexible foundation, e.g. steel frame)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 4.5<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">4.5 \u2013 11.2<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">11.2 \u2013 28<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 28<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udccc How to Use This Table<\/div>\n<p><strong>Step 1:<\/strong> Determine your machine class by power and foundation type.<br>\n<strong>Step 2:<\/strong> Measure overall vibration velocity (mm\/s RMS) on each bearing housing in radial direction.<br>\n<strong>Step 3:<\/strong> Find the zone. <strong>Zone A<\/strong> = newly commissioned or excellent. <strong>Zone B<\/strong> = unrestricted long-term operation. <strong>Zone C<\/strong> = acceptable only for limited periods \u2014 schedule maintenance. <strong>Zone D<\/strong> = damage is occurring \u2014 stop machine as soon as possible.<\/p>\n<p style=\"margin-top:8px;\">Remember: <strong>trends matter more than absolute values.<\/strong> A machine running at 3.0 mm\/s (Zone B for Class II) that was previously at 1.5 mm\/s has doubled \u2014 investigate the cause even though it's still \"acceptable.\" The Balanset-1A's vibrometer mode (F5) displays overall velocity V1s for instant zone assessment.<\/p>\n<\/div>\n\n<div class=\"info-box warning\">\n<div class=\"box-title\">\u26a0\ufe0f ISO 10816 vs. ISO 20816<\/div>\n<p>ISO 10816 was formally superseded by ISO 20816 (published 2016\u20132022). The zone boundaries remain similar for most machine types, but ISO 20816 adds evaluation criteria for displacement and expands machine-specific parts. In practice, ISO 10816 values remain the industry-standard reference. Both the Balanset-1A and most industrial vibration programs still use ISO 10816 zones.<\/p>\n<\/div>\n\n<h2 id=\"monitoring\">From Measurement to Monitoring<\/h2>\n<h3>Trend Analysis<\/h3>\n<p>A single spectrum is a snapshot. The power of vibration analysis is <strong>trend analysis<\/strong> \u2014 tracking changes over time.<\/p>\n<ul>\n<li><strong>Create a baseline:<\/strong> Measure new or known-good equipment. Save spectrums.<\/li>\n<li><strong>Establish intervals:<\/strong> Critical: weekly. Standard: monthly. Auxiliary: quarterly.<\/li>\n<li><strong>Ensure repeatability:<\/strong> Same points, same directions, same operating conditions.<\/li>\n<li><strong>Track changes:<\/strong> A 2\u00d7 increase from baseline is significant even if in ISO Zone A.<\/li>\n<\/ul>\n\n<h3>Decision Algorithm<\/h3>\n<ol>\n<li>Get a quality spectrum (F8 Charts, radial + axial).<\/li>\n<li>Identify the highest peak \u2014 this is the dominant problem.<\/li>\n<li>Match to fault type:\n <ul>\n <li><strong>1\u00d7 dominates \u2192<\/strong> Unbalance \u2192 Balance with Balanset-1A.<\/li>\n <li><strong>2\u00d7 dominates + high axial \u2192<\/strong> Misalignment \u2192 Realign shafts.<\/li>\n <li><strong>Many harmonics \u2192<\/strong> Looseness \u2192 Inspect and tighten.<\/li>\n <li><strong>Non-synchronous peaks \u2192<\/strong> Bearing \u2192 Plan replacement.<\/li>\n <li><strong>GMF + sidebands \u2192<\/strong> Gear \u2192 Check oil, inspect gearbox.<\/li>\n <\/ul>\n<\/li>\n<li>Fix the dominant fault first \u2014 secondary symptoms often disappear.<\/li>\n<\/ol>\n\n<hr style=\"margin:48px 0 24px;border:none;border-top:1px solid var(--border-light);\">\n<p><a href=\"https:\/\/vibromera.eu\/glossary\/\">\u2190 Back to Glossary Index<\/a><\/p>\n<\/article>\n\n<aside class=\"toc-sidebar\">\n<div class=\"toc-box\">\n<h3>On This Page<\/h3>\n<a href=\"#calculators\">Calculators<\/a>\n<a class=\"sub\" href=\"#calculators\">Bearing frequencies<\/a>\n<a class=\"sub\" href=\"#calculators\">ISO 10816 severity<\/a>\n<a class=\"sub\" href=\"#calculators\">RPM\u2194Hz converter<\/a>\n<a class=\"sub\" href=\"#calculators\">Gear Mesh Frequency<\/a>\n<a href=\"#fault-table\">Fault Reference Table<\/a>\n<a href=\"#fft-demo\">Interactive FFT Demo<\/a>\n<a href=\"#fundamentals\">FFT Basics<\/a>\n<a href=\"#units\">Vibration Units<\/a>\n<a href=\"#measurement\">Measurement Technique<\/a>\n<a href=\"#unbalance\">Unbalance (+ spectrums)<\/a>\n<a href=\"#misalignment\">Misalignment (+ spectrums)<\/a>\n<a href=\"#looseness\">Looseness (+ spectrums)<\/a>\n<a href=\"#bearings\">Bearing Defects (+ spectrums)<\/a>\n<a href=\"#gears\">Gear Defects (+ spectrums)<\/a>\n<a href=\"#electrical\">Electrical Faults<\/a>\n<a href=\"#belt\">Belt Drive Problems<\/a>\n<a href=\"#cavitation\">Pump Cavitation<\/a>\n<a href=\"#oilwhirl\">Oil Whirl \/ Oil Whip<\/a>\n<a href=\"#phase\">Phase Analysis<\/a>\n<a href=\"#envelope\">Envelope (Demodulation)<\/a>\n<a href=\"#iso-full\">ISO 10816 Full Table<\/a>\n<a href=\"#monitoring\">Monitoring & Trends<\/a>\n<a href=\"#faq\">FAQ (8 Questions)<\/a>\n<\/div>\n<div class=\"toc-box\" style=\"margin-top:24px;background:var(--navy);border-color:var(--navy);\">\n<h3 style=\"color:#fff;\">Vibration Analyser + Balancer<\/h3>\n<p style=\"color:rgba(255,255,255,.6);font-size:13px;margin-bottom:12px;\">2-channel FFT spectrum analyser, vibrometer, single & two-plane balancing, ISO 1940 tolerance \u2014 all in one portable kit.<\/p>\n<a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\" style=\"display:block;padding:8px 14px;background:var(--blue);color:white;border-radius:6px;text-align:center;font-weight:600;font-size:14px;text-decoration:none;margin-bottom:8px;border-left:none;\">Balanset-1A \u2192<\/a>\n<a href=\"https:\/\/vibromera.eu\/product\/balanset-4\/\" style=\"display:block;padding:8px 14px;background:rgba(255,255,255,.1);color:white;border-radius:6px;text-align:center;font-weight:600;font-size:14px;text-decoration:none;border:1px solid rgba(255,255,255,.2);border-left:none;\">Balanset-4 \u2192<\/a>\n<\/div>\n<\/aside>\n<\/div>\n<\/div>\n<\/main>\n\n\n<section class=\"section-bg alt\" id=\"faq\">\n<div class=\"container\" style=\"max-width:1000px;\">\n<div class=\"section-header\"><h2>Frequently Asked Questions \u2014 Vibration Analysis<\/h2><\/div>\n<div style=\"display:flex;flex-direction:column;gap:16px;\" id=\"faq-list\">\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What is vibration analysis?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">The process of measuring and interpreting mechanical oscillations to diagnose machinery faults without disassembly. FFT decomposes complex vibration into frequency components. Each fault produces a characteristic spectral \"fingerprint\" \u2014 unbalance at 1\u00d7 RPM, misalignment at 2\u00d7, looseness as multiple harmonics, bearing defects at non-synchronous frequencies.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> How do I tell unbalance from misalignment?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\"><strong>Unbalance:<\/strong> dominant 1\u00d7 peak, radial, stable phase, amplitude \u221d speed\u00b2. <strong>Misalignment:<\/strong> significant 2\u00d7 (often \u2265 1\u00d7), high axial vibration, 180\u00b0 phase across coupling.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What are bearing defect frequencies?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Frequencies generated when rolling elements pass over defects. BPFO = outer race, BPFI = inner race, BSF = ball\/roller, FTF = cage. They are NOT integer multiples of shaft speed. Use the bearing frequency calculator above.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What is a good vibration level?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\"><a href=\"https:\/\/vibromera.eu\/glossary\/iso-10816-1\/\">ISO 10816<\/a> zones for Class II (15\u201375 kW): A < 1.8, B < 4.5, C < 11.2, D > 11.2 mm\/s RMS. Trends matter more \u2014 a 2\u00d7 increase from baseline is significant even in Zone A.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> Can Balanset-1A do vibration analysis?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Yes. 2-channel FFT spectrum analyser (F1), vibrometer (F5), detailed charts (F8). Mount both sensors radial+axial on one bearing for instant misalignment detection.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> Time waveform vs. FFT spectrum?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Waveform shows amplitude vs. time \u2014 complex when multiple faults overlap. FFT decomposes into individual frequencies (like a prism splitting light). Each spectrum peak = one vibration source.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> How often should I measure vibration?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Critical: weekly. Standard: monthly. Auxiliary: quarterly. After maintenance: immediately. Consistency is key \u2014 same points, directions, conditions.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What causes 0.5\u00d7 (subharmonic) vibration?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Severe mechanical looseness, oil whirl in journal bearings, or cracked shaft. Half-order peaks (0.5\u00d7, 1.5\u00d7) arise from impacts every other revolution. Serious condition \u2014 prompt attention required.<\/div><\/details>\n<\/div>\n<\/div>\n<\/section>\n\n\n<section style=\"padding:32px 0;background:var(--white);border-top:1px solid var(--border-light);\">\n<div class=\"container\" style=\"max-width:1000px;\">\n<h3 style=\"font-family:'DM Serif Display',serif;font-size:22px;color:var(--navy);margin-bottom:20px;\">Related Glossary Articles<\/h3>\n<div style=\"display:grid;grid-template-columns:repeat(3,1fr);gap:16px;\">\n<a href=\"https:\/\/vibromera.eu\/glossary\/balancing\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Rotor Balancing<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">The procedure when spectrum says \"unbalance\"<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/iso-10816-1\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">ISO 10816-1<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">Vibration severity zones and classification<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/unbalance\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Unbalance<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">The most common vibration source<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/iso-1940-1\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">ISO 1940-1<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">G-grade tolerances after balancing<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/natural-frequency\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Natural Frequency<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">Resonance and critical speeds<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/bearing-fault-frequencies\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Bearing Fault Frequencies<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">BPFO, BPFI, BSF, FTF in detail<\/div><\/a>\n<\/div>\n<\/div>\n<\/section>\n\n<section class=\"shop-cta\">\n<div class=\"container\">\n<h2>Diagnose First \u2014 Then Balance<\/h2>\n<p>The Balanset-1A is both a 2-channel vibration analyser and a precision field balancer. Identify the fault by spectrum, then fix it \u2014 all with one instrument.<\/p>\n<a href=\"https:\/\/vibromera.eu\/shop\/\" class=\"cta-btn\">Browse Equipment \u2192<\/a>\n<\/div>\n<\/section>\n\n<footer class=\"page-footer\">\n<div class=\"container\"><p><a href=\"https:\/\/vibromera.eu\/glossary\/\">\u2190 Back to Glossary<\/a> | <a href=\"https:\/\/vibromera.eu\/\">vibromera.eu<\/a><\/p><\/div>\n<\/footer>\n\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/chart.js\"><\/script>\n<script>\n\/* ===== BEARING PRESET ===== *\/\nfunction applyBearingPreset(){\n var v=document.getElementById('bc-preset').value;\n if(!v)return;\n var p=v.split(',');\n document.getElementById('bc-balls').value=p[0];\n document.getElementById('bc-bd').value=p[1];\n document.getElementById('bc-pd').value=p[2];\n document.getElementById('bc-angle').value=p[3];\n calcBearing();\n}\n\n\/* ===== BEARING FREQUENCY CALCULATOR ===== *\/\nfunction calcBearing(){\n var rpm=parseFloat(document.getElementById('bc-rpm').value)||0;\n var n=parseFloat(document.getElementById('bc-balls').value)||0;\n var bd=parseFloat(document.getElementById('bc-bd').value)||0;\n var pd=parseFloat(document.getElementById('bc-pd').value)||0;\n var a=(parseFloat(document.getElementById('bc-angle').value)||0)*Math.PI\/180;\n var fs=rpm\/60,r=bd\/pd,ca=Math.cos(a);\n var bpfo=n\/2*(1-r*ca)*fs;\n var bpfi=n\/2*(1+r*ca)*fs;\n var bsf=pd\/(2*bd)*(1-Math.pow(r*ca,2))*fs;\n var ftf=0.5*(1-r*ca)*fs;\n document.getElementById('bc-bpfo').textContent=bpfo.toFixed(2);\n document.getElementById('bc-bpfi').textContent=bpfi.toFixed(2);\n document.getElementById('bc-bsf').textContent=bsf.toFixed(2);\n document.getElementById('bc-ftf').textContent=ftf.toFixed(2);\n document.getElementById('bc-1x').textContent=fs.toFixed(2);\n document.getElementById('bc-ratio').textContent=(bpfo>0&&bpfi>0)?(bpfi\/bpfo).toFixed(3):'\u2014';\n document.getElementById('bc-results').classList.add('active');\n}\n\n\/* ===== ISO 10816 SEVERITY ===== *\/\nvar sevData={\n '1':{limits:[0.71,1.8,4.5],name:'Class I (\u2264 15 kW)'},\n '2':{limits:[1.8,4.5,11.2],name:'Class II (15\u201375 kW)'},\n '3':{limits:[2.8,7.1,18],name:'Class III (large, rigid)'},\n '4':{limits:[4.5,11.2,28],name:'Class IV (large, flexible)'}\n};\nfunction calcSeverity(){\n var vel=parseFloat(document.getElementById('sev-vel').value)||0;\n var cls=document.getElementById('sev-class').value;\n var d=sevData[cls];var zone,zc,label;\n if(vel<=d.limits[0]){zone='A';zc='zone-a';label='Zone A \u2014 Good. Newly commissioned or excellent condition.';}\n else if(vel<=d.limits[1]){zone='B';zc='zone-b';label='Zone B \u2014 Acceptable. Unrestricted long-term operation.';}\n else if(vel<=d.limits[2]){zone='C';zc='zone-c';label='Zone C \u2014 Alert! Plan corrective action.';}\n else{zone='D';zc='zone-d';label='Zone D \u2014 Danger! Immediate action required.';}\n var el=document.getElementById('sev-result');el.style.display='block';el.className='severity-result '+zc;\n el.innerHTML='<strong>'+vel+' mm\/s \u2192 '+zone+'<\/strong> ('+d.name+')<br>'+label+'<br><span style=\"font-size:12px;opacity:.7;\">Limits: A\/B='+d.limits[0]+' | B\/C='+d.limits[1]+' | C\/D='+d.limits[2]+' mm\/s<\/span>';\n}\n\n\/* ===== RPM \u2194 Hz ===== *\/\nfunction convRPM(){var rpm=parseFloat(document.getElementById('conv-rpm').value)||0;var hz=rpm\/60;document.getElementById('conv-hz').value=hz.toFixed(2);updConv(hz);}\nfunction convHz(){var hz=parseFloat(document.getElementById('conv-hz').value)||0;document.getElementById('conv-rpm').value=Math.round(hz*60);updConv(hz);}\nfunction updConv(hz){document.getElementById('conv-1x').textContent=hz.toFixed(2);document.getElementById('conv-2x').textContent=(hz*2).toFixed(2);document.getElementById('conv-3x').textContent=(hz*3).toFixed(2);document.getElementById('conv-period').textContent=hz>0?(1000\/hz).toFixed(2):'\u221e';}\n\n\/* ===== GMF CALCULATOR ===== *\/\nfunction calcGMF(){\n var rpm=parseFloat(document.getElementById('gmf-rpm').value)||0;\n var t1=parseFloat(document.getElementById('gmf-teeth1').value)||0;\n var t2=parseFloat(document.getElementById('gmf-teeth2').value)||0;\n var fs=rpm\/60;var gmf=t1*fs;\n document.getElementById('gmf-val').textContent=gmf.toFixed(1);\n document.getElementById('gmf-2x').textContent=(gmf*2).toFixed(1);\n document.getElementById('gmf-3x').textContent=(gmf*3).toFixed(1);\n document.getElementById('gmf-ratio').textContent=t2>0?(t2\/t1).toFixed(2):'\u2014';\n document.getElementById('gmf-driven').textContent=t2>0?((rpm*t1\/t2).toFixed(1)):'\u2014';\n document.getElementById('gmf-results').classList.add('active');\n}\n\n\/* ===== INTERACTIVE FFT DEMO \u2014 16 FAULT SCENARIOS ===== *\/\n(function(){\n \/* Frequency indices: 1\u00d7=index 2 (at 10Hz steps \u2192 25Hz mapped to ~index2), etc.\n For 50-bin display: bin i \u2192 (i+1)*10 Hz label. 1\u00d7\u224825Hz\u2192i=2, 2\u00d7\u224850Hz\u2192i=4, 3\u00d7\u224875Hz\u2192i=6, etc.\n BPFO\u224889Hz\u2192i=8, BPFI\u2248136Hz\u2192i=13, BSF\u224859Hz\u2192i=5, FTF\u224810Hz\u2192i=0\n GMF=500Hz\u2192i=49(cap at 50) \u2014 use i=48\/49 for GMF range\n Belt freq\u22488Hz\u2192i=0, 2\u00d7belt=16Hz\u2192i=1\n Oil whirl 0.43\u00d7\u224810.7Hz\u2192i=0 *\/\n\n var F={\n \/* === BASELINE === *\/\n normal:{\n d:'Normal \u2014 small 1\u00d7 from residual unbalance. Clean spectrum with low noise floor. All peaks below 1 mm\/s.',\n t:function(x){return .5*Math.sin(x*.2)+(Math.random()-.5)*.15;},\n f:[{i:2,a:.5}]},\n\n \/* === UNBALANCE === *\/\n unbal_static:{\n d:'Static unbalance \u2014 dominant 1\u00d7 peak (25 Hz at 1500 RPM). Pure sinusoid, nearly zero harmonics. Both bearings in-phase. Amplitude \u221d speed\u00b2.',\n t:function(x){return 8.5*Math.sin(x*.2)+(Math.random()-.5)*.3;},\n f:[{i:2,a:8.5},{i:4,a:.3}]},\n\n unbal_dynamic:{\n d:'Dynamic (couple) unbalance \u2014 1\u00d7 dominant like static, but with slight 2\u00d7 from couple component. Bearings ~180\u00b0 out of phase. Two-plane correction needed.',\n t:function(x){return 7*Math.sin(x*.2)+1.5*Math.sin(x*.4+1.2)+(Math.random()-.5)*.4;},\n t2:function(x){return 7*Math.sin(x*.2+Math.PI)+1.5*Math.sin(x*.4+1.2+Math.PI)+(Math.random()-.5)*.4;},\n f:[{i:2,a:7.0},{i:4,a:1.5}]},\n\n \/* === MISALIGNMENT === *\/\n misal_parallel:{\n d:'Parallel misalignment \u2014 2\u00d7 peak \u2265 1\u00d7 in radial direction. 180\u00b0 phase shift across coupling. Waveform is M-shaped (two peaks per revolution).',\n t:function(x){return 4*Math.sin(x*.2)+7*Math.sin(x*.4)+1.2*Math.sin(x*.6)+(Math.random()-.5)*.5;},\n t2:function(x){return 4*Math.sin(x*.2+Math.PI)+7*Math.sin(x*.4+Math.PI)+1.2*Math.sin(x*.6+Math.PI)+(Math.random()-.5)*.5;},\n f:[{i:2,a:4.0},{i:4,a:7.0},{i:6,a:1.2}]},\n\n misal_angular:{\n d:'Angular misalignment \u2014 high 1\u00d7 and 2\u00d7 in axial direction. Axial vibration \u2265 50% of radial. 180\u00b0 axial phase across coupling. Strong 3\u00d7 may appear.',\n t:function(x){return 5*Math.sin(x*.2)+5.5*Math.sin(x*.4)+2.5*Math.sin(x*.6)+(Math.random()-.5)*.5;},\n t2:function(x){return 5*Math.sin(x*.2+Math.PI)+5.5*Math.sin(x*.4+Math.PI)+2.5*Math.sin(x*.6+Math.PI)+(Math.random()-.5)*.5;},\n f:[{i:2,a:5.0},{i:4,a:5.5},{i:6,a:2.5},{i:8,a:.6}]},\n\n \/* === LOOSENESS === *\/\n loose_component:{\n d:'Component looseness \u2014 \"forest\" of harmonics from 1\u00d7 to 10\u00d7+. Sub-harmonic at 0.5\u00d7 indicates impacts every other revolution. Waveform is truncated\/impulsive.',\n t:function(x){var s=0;for(var k=1;k<=8;k++)s+=(4\/k)*Math.sin(x*.2*k+k*.3);s+=1.2*Math.sin(x*.1);return s+(Math.random()-.5)*1.2;},\n f:[{i:0,a:.5},{i:1,a:1.2},{i:2,a:4.0},{i:4,a:3.2},{i:6,a:2.6},{i:8,a:2.1},{i:10,a:1.7},{i:12,a:1.4},{i:14,a:1.1},{i:16,a:.9},{i:18,a:.7},{i:20,a:.5}]},\n\n loose_structural:{\n d:'Structural looseness \u2014 1\u00d7 and 2\u00d7 dominant, few higher harmonics. Strong vertical direction. Phase may be unstable. Often confused with misalignment \u2014 bolt check test differentiates.',\n t:function(x){return 5.5*Math.sin(x*.2)+3.5*Math.sin(x*.4)+.8*Math.sin(x*.6)+(Math.random()-.5)*.6;},\n f:[{i:2,a:5.5},{i:4,a:3.5},{i:6,a:.8}]},\n\n \/* === BEARINGS === *\/\n bear_outer:{\n d:'Outer race defect (BPFO) \u2014 evenly spaced non-synchronous peaks at BPFO harmonics. No 1\u00d7 sidebands (outer ring is stationary). Most common bearing fault (~80% of defects).',\n t:function(x){return .3*Math.sin(x*.2)+1.8*Math.sin(x*2.26)+1.4*Math.sin(x*4.52)+1.0*Math.sin(x*6.78)+.7*Math.sin(x*9.04)+(Math.random()-.5)*1.0;},\n f:[{i:2,a:.3},{i:9,a:2.0},{i:18,a:1.7},{i:27,a:1.4},{i:36,a:1.0},{i:45,a:.7}]},\n\n bear_inner:{\n d:'Inner race defect (BPFI) \u2014 BPFI harmonics with \u00b11\u00d7 sidebands (smaller peaks flanking main peaks). Sidebands arise from load zone modulation as the rotating inner ring carries the defect through the load zone.',\n t:function(x){var imp=Math.sin(x*3.45);var mod=1+.5*Math.sin(x*.2);return .3*Math.sin(x*.2)+imp*mod*1.6+(Math.random()-.5)*.8;},\n f:[{i:2,a:.4},{i:11,a:.5},{i:13,a:1.8},{i:15,a:.5},{i:24,a:.3},{i:26,a:1.3},{i:28,a:.3},{i:39,a:.9}]},\n\n bear_rolling:{\n d:'Rolling element defect (BSF) \u2014 BSF harmonics, 2\u00d7BSF often higher than 1\u00d7BSF (defect strikes both races per revolution). Non-synchronous. Often accompanied by race damage in later stages.',\n t:function(x){return .2*Math.sin(x*.2)+.8*Math.sin(x*1.49)+2.0*Math.sin(x*2.98)+1.1*Math.sin(x*4.47)+(Math.random()-.5)*1.0;},\n f:[{i:2,a:.3},{i:6,a:1.0},{i:12,a:2.2},{i:18,a:1.3},{i:24,a:.7}]},\n\n bear_cage:{\n d:'Cage (train) defect (FTF) \u2014 sub-synchronous peaks at FTF \u2248 0.4\u00d7 shaft speed. Very low frequency. FTF harmonics may appear. Usually accompanies other bearing damage \u2014 rare in isolation.',\n t:function(x){return 2.0*Math.sin(x*.08)+.7*Math.sin(x*.16)+.3*Math.sin(x*.24)+.5*Math.sin(x*.2)+(Math.random()-.5)*.5;},\n f:[{i:0,a:2.2},{i:1,a:.8},{i:2,a:.5},{i:3,a:.3}]},\n\n \/* === GEARS === *\/\n gear_healthy:{\n d:'Healthy gear mesh \u2014 clean GMF peak at teeth \u00d7 shaft speed. No sidebands. Low, single peak indicates normal meshing. GMF amplitude depends on load and gear quality.',\n t:function(x){return .5*Math.sin(x*.2)+2.0*Math.sin(x*6.28)+(Math.random()-.5)*.3;},\n f:[{i:2,a:.5},{i:48,a:2.5}]},\n\n gear_worn:{\n d:'Worn\/damaged gear \u2014 GMF with multiple \u00b11\u00d7 sidebands and 2nd GMF harmonic. Sideband count and amplitude correlate with severity. Dense sidebands = advanced wear or broken tooth.',\n t:function(x){return .8*Math.sin(x*.2)+3.0*Math.sin(x*6.28)*(1+.4*Math.sin(x*.2))+1.5*Math.sin(x*12.56)*(1+.3*Math.sin(x*.2))+(Math.random()-.5)*.6;},\n f:[{i:2,a:.8},{i:46,a:.7},{i:47,a:1.0},{i:48,a:3.5},{i:49,a:1.0},{i:44,a:.4}]},\n\n \/* === OTHER === *\/\n electrical:{\n d:'Electrical fault \u2014 peak at 2\u00d7 line frequency (100 Hz on 50 Hz grid, 120 Hz on 60 Hz). Disappears instantly when power is cut \u2014 mechanical faults decay gradually over seconds.',\n t:function(x){return 1*Math.sin(x*.2)+5.5*Math.sin(x*.628)+(Math.random()-.5)*.3;},\n f:[{i:2,a:1.0},{i:10,a:5.5}]},\n\n belt:{\n d:'Belt drive defect \u2014 sub-synchronous peaks at belt frequency and harmonics (all below 1\u00d7 shaft speed). Belt frequency = \u03c0\u00b7D\u00b7RPM \/ (60\u00b7L). May also show elevated 1\u00d7 from pulley eccentricity.',\n t:function(x){return 2.0*Math.sin(x*.1)+1.5*Math.sin(x*.2)+1.0*Math.sin(x*.3)+.6*Math.sin(x*.4)+(Math.random()-.5)*.4;},\n f:[{i:0,a:2.0},{i:1,a:2.6},{i:2,a:1.0},{i:3,a:.7},{i:4,a:.4}]},\n\n cavitation:{\n d:'Pump cavitation \u2014 broadband high-frequency noise with no discrete peaks. Random bubble collapse creates elevated noise floor above ~200 Hz. Sounds like \"gravel in pump.\" No harmonic structure.',\n t:function(x){return .5*Math.sin(x*.2)+(Math.random()-.5)*4.0;},\n f:(function(){var p=[{i:2,a:.6}];for(var j=15;j<50;j++)p.push({i:j,a:.6+Math.random()*1.8});return p;})()},\n\n oilwhirl:{\n d:'Oil whirl (journal bearings) \u2014 sub-synchronous peak at ~0.43\u00d7 shaft speed (\u2248 10.7 Hz for 1500 RPM). Tracks with speed (proportional). Precursor to destructive oil whip. Only in sleeve\/journal bearings.',\n t:function(x){return 3.5*Math.sin(x*.086)+1.2*Math.sin(x*.2)+(Math.random()-.5)*.5;},\n f:[{i:0,a:3.5},{i:2,a:1.2},{i:4,a:.3}]}\n };\n\n var tc,fc;\n function init(){\n var a=document.getElementById('demo-time'),b=document.getElementById('demo-fft');if(!a||!b)return;\n var tL=[];for(var i=0;i<250;i++)tL.push(i);\n tc=new Chart(a,{type:'line',data:{labels:tL,datasets:[{data:[],borderColor:'#2563eb',backgroundColor:'rgba(37,99,235,.08)',borderWidth:2,pointRadius:0,fill:true},{data:[],borderColor:'#dc2626',backgroundColor:'rgba(220,38,38,.06)',borderWidth:2,pointRadius:0,fill:false,hidden:true}]},options:{responsive:true,maintainAspectRatio:false,animation:{duration:400},plugins:{legend:{display:false},tooltip:{enabled:false}},scales:{x:{grid:{color:'#e2e8f0'},ticks:{display:false},title:{display:true,text:'Time',color:'#94a3b8',font:{size:11}}},y:{grid:{color:'#e2e8f0'},ticks:{color:'#94a3b8',font:{size:10}},title:{display:true,text:'mm\/s',color:'#94a3b8',font:{size:11}}}}}});\n var fL=[];for(var j=1;j<=50;j++)fL.push(j*10);\n fc=new Chart(b,{type:'bar',data:{labels:fL,datasets:[{data:[],backgroundColor:'#2563eb',borderColor:'#1d4ed8',borderWidth:1,barPercentage:1,categoryPercentage:1}]},options:{responsive:true,maintainAspectRatio:false,animation:{duration:400},plugins:{legend:{display:false},tooltip:{callbacks:{title:function(t){return t[0].label+' Hz';},label:function(t){return t.raw.toFixed(2)+' mm\/s';}}}},scales:{x:{grid:{display:false},ticks:{color:'#94a3b8',font:{size:10},maxRotation:0,autoSkip:true,maxTicksLimit:15},title:{display:true,text:'Frequency (Hz)',color:'#94a3b8',font:{size:11}}},y:{beginAtZero:true,grid:{color:'#e2e8f0'},ticks:{color:'#94a3b8',font:{size:10}},title:{display:true,text:'mm\/s',color:'#94a3b8',font:{size:11}}}}}});\n upd('normal');\n document.querySelectorAll('.demo-btn').forEach(function(b){b.addEventListener('click',function(){document.querySelectorAll('.demo-btn').forEach(function(x){x.classList.remove('active');});b.classList.add('active');upd(b.getAttribute('data-fault'));});});\n }\n function upd(type){\n var f=F[type];if(!f)return;\n document.getElementById('demo-desc').textContent=f.d;\n var td=[];for(var i=0;i<250;i++)td.push(f.t(i));\n tc.data.datasets[0].data=td;var all=td.slice();if(f.t2){var td2=[];for(var i=0;i<250;i++)td2.push(f.t2(i));tc.data.datasets[1].data=td2;tc.data.datasets[1].hidden=false;all=all.concat(td2);}else{tc.data.datasets[1].data=[];tc.data.datasets[1].hidden=true;}var mx=Math.max(Math.abs(Math.min.apply(null,all)),Math.max.apply(null,all))*1.2;\n tc.options.scales.y.min=-mx;tc.options.scales.y.max=mx;tc.update();\n var fd=new Array(50).fill(0).map(function(){return Math.random()*.08;});\n var fftData=typeof f.f==='function'?f.f():f.f;\n fftData.forEach(function(p){if(p.i>=0&&p.i<50)fd[p.i]=p.a;});\n fc.data.datasets[0].data=fd;fc.options.scales.y.max=Math.ceil(Math.max.apply(null,fd)*1.3);fc.update();\n }\n if(document.readyState==='loading')document.addEventListener('DOMContentLoaded',init);else init();\n})();\n\n\/* ===== REFERENCE SPECTRUM CHARTS ===== *\/\ndocument.addEventListener('DOMContentLoaded',function(){\n var step=5,size=200,freqRange=1000;\n var labels=[];for(var i=1;i<=size;i++)labels.push(i*step);\n\n function noise(n){var d=[];for(var j=0;j<n;j++)d.push(Math.random()*.15);return d;}\n function mkSpec(peaks){var d=noise(size);peaks.forEach(function(p){if(p.i>=0&&p.i<size)d[p.i]=p.a;});return d;}\n\n function bar(id,peaks,yMax,color,title){\n var el=document.getElementById(id);if(!el)return;\n new Chart(el,{type:'bar',data:{labels:labels,datasets:[{data:mkSpec(peaks),backgroundColor:color||'#2563eb',borderColor:color?color:'#1d4ed8',borderWidth:1,barPercentage:1,categoryPercentage:1}]},options:{responsive:true,maintainAspectRatio:false,animation:{duration:600},plugins:{legend:{display:false},title:{display:!!title,text:title||'',color:'#0a2540',font:{size:13,weight:'bold'}},tooltip:{callbacks:{title:function(t){return t[0].label+' Hz';},label:function(t){return t.raw.toFixed(2)+' mm\/s';}}}},scales:{x:{grid:{display:false},ticks:{color:'#94a3b8',font:{size:9},maxRotation:0,autoSkip:true,maxTicksLimit:20},title:{display:true,text:'Frequency (Hz)',color:'#64748b',font:{size:11}}},y:{beginAtZero:true,max:yMax,grid:{color:'#e2e8f0'},ticks:{color:'#94a3b8',font:{size:10}},title:{display:true,text:'Amplitude (mm\/s)',color:'#64748b',font:{size:11}}}}}});\n }\n\n \/* 1\u00d7 = 25 Hz = index 4 (5Hz step), 2\u00d7 = 50Hz = index 9, 3\u00d7=75Hz=14, etc. *\/\n\n \/* UNBALANCE *\/\n bar('ch-unbal-static',[{i:4,a:8.0}],10,'#2563eb','Static Unbalance');\n bar('ch-unbal-dynamic',[{i:4,a:8.5},{i:9,a:0.5}],10,'#2563eb','Dynamic Unbalance');\n\n \/* MISALIGNMENT *\/\n bar('ch-misal-parallel',[{i:4,a:7.0},{i:9,a:4.5},{i:14,a:2.0}],8,'#d97706','Parallel Misalignment \u2014 Radial');\n bar('ch-misal-angular-r',[{i:4,a:3.0},{i:9,a:7.5},{i:14,a:1.5}],9,'#d97706','Angular Misalignment \u2014 Radial');\n bar('ch-misal-angular-a',[{i:4,a:2.0},{i:9,a:9.0},{i:14,a:2.5}],10,'#e83e8c','Angular Misalignment \u2014 Axial');\n\n \/* LOOSENESS *\/\n var loosePeaks=[{i:1,a:1.0}]; \/* 0.5\u00d7 subharmonic *\/\n for(var k=1;k<=10;k++)loosePeaks.push({i:k*5-1,a:4.0-k*0.32});\n bar('ch-loose-component',loosePeaks,5,'#dc2626','Component Looseness');\n bar('ch-loose-structural',[{i:4,a:5.0},{i:9,a:4.0},{i:14,a:0.8}],6,'#dc2626','Structural Looseness');\n\n \/* BEARINGS \u2014 realistic non-synchronous frequencies *\/\n \/* Assume 6205 @ 1500 RPM: BPFO\u224889Hz(i=17), BPFI\u2248136Hz(i=27), BSF\u224859Hz(i=11), FTF\u224810Hz(i=1) *\/\n bar('ch-bear-outer',[{i:17,a:2.2},{i:35,a:1.9},{i:53,a:1.6},{i:71,a:1.3},{i:89,a:1.0}],3,'#7c3aed','Outer Race (BPFO) \u2014 6205 @ 1500 RPM');\n\n \/* BPFI with \u00b11\u00d7 sidebands (1\u00d7=25Hz=5 bins) *\/\n var bpfiPeaks=[];\n for(var h=1;h<=5;h++){\n var bi=27*h-1;var amp=2.5-h*0.35;\n if(bi<size){bpfiPeaks.push({i:bi,a:amp});if(bi-5>=0)bpfiPeaks.push({i:bi-5,a:amp*0.35});if(bi+5<size)bpfiPeaks.push({i:bi+5,a:amp*0.35});}\n }\n bar('ch-bear-inner',bpfiPeaks,3,'#7c3aed','Inner Race (BPFI) with \u00b11\u00d7 Sidebands');\n\n bar('ch-bear-rolling',[{i:11,a:1.0},{i:23,a:2.5},{i:35,a:1.2},{i:47,a:0.8}],3,'#7c3aed','Rolling Element (BSF) \u2014 2\u00d7BSF Dominant');\n bar('ch-bear-cage',[{i:1,a:1.8},{i:3,a:0.9},{i:5,a:0.5}],2.5,'#7c3aed','Cage (FTF) \u2014 Sub-synchronous');\n\n \/* GEARS \u2014 GMF = 20teeth \u00d7 25Hz = 500Hz = index 99 *\/\n bar('ch-gear-eccentric',[{i:4,a:1.5},{i:94,a:1.2},{i:99,a:3.5},{i:104,a:1.2}],4.5,'#0a2540','Gear Eccentricity \u2014 GMF \u00b1 1\u00d7');\n bar('ch-gear-wear',[{i:94,a:0.8},{i:99,a:3.5},{i:104,a:0.8},{i:193,a:2.0},{i:188,a:0.6},{i:198,a:0.6}],4.5,'#0a2540','Gear Wear \u2014 GMF + 2\u00d7GMF with Sidebands');\n\n \/* ENVELOPE \u2014 demodulated bearing spectrum, clean BPFI harmonics *\/\n var envPeaks=[];\n for(var e=1;e<=8;e++){var ei=27*e-1;if(ei<size)envPeaks.push({i:ei,a:2.8-e*0.28});}\n bar('ch-envelope',envPeaks,3.5,'#059669','Envelope Spectrum \u2014 BPFI Harmonics (Demodulated)');\n\n \/* BELT DRIVE \u2014 sub-synchronous belt freq + harmonics *\/\n \/* Belt freq ~8 Hz = index 1, 2\u00d7belt=16Hz=index 2, 3\u00d7belt=24Hz=index 3 (below 1\u00d7 at index 4) *\/\n bar('ch-belt',[{i:0,a:1.8},{i:1,a:2.5},{i:2,a:1.6},{i:3,a:1.0},{i:4,a:0.6},{i:5,a:0.4}],3.5,'#0891b2','Belt Drive \u2014 Belt Frequency Harmonics (sub-synchronous)');\n\n \/* CAVITATION \u2014 broadband high-frequency hump *\/\n var cavPeaks=[];\n for(var c=40;c<180;c++){cavPeaks.push({i:c,a:0.5+Math.random()*1.2});}\n cavPeaks.push({i:4,a:0.8}); \/* small 1\u00d7 from shaft *\/\n bar('ch-cavitation',cavPeaks,2.5,'#0d9488','Pump Cavitation \u2014 Broadband High-Frequency Noise');\n\n \/* OIL WHIRL \u2014 peak at ~0.43\u00d7 = ~10.7Hz \u2248 index 1 (5Hz step) *\/\n bar('ch-oilwhirl',[{i:1,a:3.2},{i:3,a:0.6},{i:4,a:1.5},{i:9,a:0.4}],4,'#a855f7','Oil Whirl \u2014 Sub-synchronous at ~0.43\u00d7 Shaft Speed');\n\n \/* Auto-calc on load *\/\n calcBearing();calcSeverity();convRPM();\n});\n<\/script>\n<\/body>\n<\/html><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Vibration Analysis \u2014 Beginner’s Guide to Spectrum Diagnostics \u2014 Vibromera Home \u2192 Glossary \u2192 Vibration Analysis Vibration Analysis \u2014 Spectrum Diagnostics Guide \ud83d\udccc Canonical Reference Article \u2014 vibromera.eu From FFT fundamentals to fault diagnosis: learn to read vibration spectrums, calculate bearing defect frequencies, assess severity per ISO 10816, and diagnose 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\n\n\n\n\nVibration Analysis \u2014 Beginner's Guide to Spectrum Diagnostics \u2014 Vibromera<\/title>\n<meta name=\"description\" content=\"Complete vibration analysis guide: FFT spectrum interpretation, fault diagnosis (unbalance, misalignment, looseness, bearing defects), bearing frequency calculator (BPFO\/BPFI\/BSF\/FTF), ISO 10816 severity assessment, and interactive spectrum demos with Balanset-1A.\">\n<meta name=\"keywords\" content=\"vibration analysis, FFT spectrum, vibration diagnostics, bearing defect frequency, BPFO, BPFI, BSF, FTF, unbalance diagnosis, misalignment spectrum, mechanical looseness, predictive maintenance, ISO 10816, Balanset-1A, vibration analyzer, condition monitoring\">\n<meta name=\"author\" content=\"Vibromera\">\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large\">\n\n\n\n\n\n\n\n<meta property=\"og:type\" content=\"article\">\n<meta property=\"og:title\" content=\"Vibration Analysis \u2014 Spectrum Diagnostics Guide with Interactive Tools\">\n<meta property=\"og:description\" content=\"FFT spectrum interpretation, bearing frequency calculator, ISO 10816 severity checker, fault diagnosis patterns \u2014 complete beginner's guide with Balanset-1A.\">\n<meta property=\"og:url\" content=\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/\">\n<meta property=\"og:site_name\" content=\"Vibromera \u2014 Vibration Analysis & Balancing Equipment\">\n<meta property=\"og:locale\" content=\"en_US\">\n<meta property=\"og:image\" content=\"https:\/\/vibromera.eu\/wp-content\/uploads\/vibration-analysis-og.jpg\">\n<meta property=\"article:publisher\" content=\"https:\/\/vibromera.eu\/\">\n<meta property=\"article:section\" content=\"Glossary\">\n<meta property=\"article:tag\" content=\"Vibration Analysis\">\n<meta property=\"article:tag\" content=\"FFT Spectrum\">\n<meta property=\"article:tag\" content=\"Predictive Maintenance\">\n<meta name=\"twitter:card\" content=\"summary_large_image\">\n<meta name=\"twitter:title\" content=\"Vibration Analysis Guide \u2014 FFT, Bearing Frequencies & Fault Diagnosis\">\n<meta name=\"twitter:description\" content=\"Interactive bearing frequency calculator, ISO 10816 checker, FFT spectrum demos, and step-by-step fault diagnosis for rotating machinery.\">\n<meta name=\"geo.region\" content=\"EU\">\n<meta name=\"geo.placename\" content=\"Porto, Portugal\">\n<meta name=\"geo.position\" content=\"41.1579;-8.6291\">\n<meta name=\"ICBM\" content=\"41.1579, -8.6291\">\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@graph\":[\n{\"@type\":\"TechArticle\",\"@id\":\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/#article\",\"headline\":\"Vibration Analysis: Beginner's Guide to Spectrum Diagnostics with Balanset-1A\",\"description\":\"Comprehensive guide to vibration analysis and FFT spectrum interpretation for rotating machinery diagnostics. Covers unbalance, misalignment, looseness, bearing defects, gear faults with interactive calculators and spectrum demonstrations.\",\"author\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\"},\"publisher\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\",\"logo\":{\"@type\":\"ImageObject\",\"url\":\"https:\/\/vibromera.eu\/wp-content\/uploads\/vibromera-logo.png\"}},\"mainEntityOfPage\":\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/\",\"datePublished\":\"2025-09-15\",\"dateModified\":\"2026-02-07\",\"inLanguage\":\"en\",\"proficiencyLevel\":\"Beginner\",\"about\":[{\"@type\":\"Thing\",\"name\":\"Vibration Analysis\"},{\"@type\":\"Thing\",\"name\":\"FFT Spectrum Analysis\"},{\"@type\":\"Thing\",\"name\":\"Predictive Maintenance\"},{\"@type\":\"Thing\",\"name\":\"Bearing Defect Frequencies\"}]},\n{\"@type\":\"FAQPage\",\"@id\":\"https:\/\/vibromera.eu\/glossary\/vibration-analysis\/#faq\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"What is vibration analysis?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Vibration analysis is the process of measuring and interpreting mechanical oscillations of rotating machinery to diagnose faults. Using FFT (Fast Fourier Transform), the complex vibration signal is decomposed into individual frequency components. Each fault type produces a characteristic 'fingerprint' in the frequency spectrum \u2014 unbalance at 1\u00d7 RPM, misalignment at 2\u00d7, looseness as multiple harmonics, bearing defects at non-synchronous frequencies (BPFO, BPFI, BSF, FTF).\"}},\n{\"@type\":\"Question\",\"name\":\"How do I know if vibration is caused by unbalance or misalignment?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Unbalance produces a dominant peak at exactly 1\u00d7 RPM (shaft speed) in the radial direction, with stable phase and amplitude proportional to speed\u00b2. Misalignment produces significant 2\u00d7 RPM component (often equal to or larger than 1\u00d7), strong axial vibration, and 180\u00b0 phase shift across the coupling.\"}},\n{\"@type\":\"Question\",\"name\":\"What are bearing defect frequencies (BPFO, BPFI, BSF, FTF)?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"These are characteristic frequencies generated when a rolling element passes over a defect on a specific bearing component. BPFO (Ball Pass Frequency Outer race), BPFI (Ball Pass Frequency Inner race), BSF (Ball Spin Frequency), FTF (Fundamental Train Frequency). They depend on bearing geometry and shaft speed.\"}},\n{\"@type\":\"Question\",\"name\":\"What is a good vibration level for rotating machinery?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"ISO 10816-1 classifies vibration severity by machine class. For typical industrial machines (Class II, 15-75 kW): Zone A (good) < 1.8 mm\/s RMS, Zone B (acceptable) < 4.5 mm\/s, Zone C (alert) < 11.2 mm\/s, Zone D (danger) > 11.2 mm\/s.\"}},\n{\"@type\":\"Question\",\"name\":\"Can the Balanset-1A be used for vibration analysis?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes. The Balanset-1A includes a 2-channel vibration analyser with FFT spectrum display (F1 mode), vibrometer for overall\/1\u00d7 comparison (F5 mode), and detailed spectrum charts (F8 mode). Both channels can be used simultaneously for radial+axial comparison.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the difference between time waveform and FFT spectrum?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The time waveform shows vibration amplitude over time \u2014 complex when multiple faults are present. FFT decomposes this into individual frequency components, creating a spectrum where each peak corresponds to a specific source.\"}},\n{\"@type\":\"Question\",\"name\":\"How often should I measure vibration?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Critical equipment: weekly or biweekly. Standard production: monthly. Auxiliary\/non-critical: quarterly. After any maintenance: immediately to establish new baseline.\"}},\n{\"@type\":\"Question\",\"name\":\"What causes subharmonic vibration (0.5\u00d7)?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Subharmonics at 0.5\u00d7 RPM typically indicate severe mechanical looseness, oil whirl in journal bearings, or cracked shafts. Half-order peaks arise from impacts occurring every other revolution.\"}}\n]},\n{\"@type\":\"BreadcrumbList\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/vibromera.eu\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Glossary\",\"item\":\"https:\/\/vibromera.eu\/glossary\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Vibration Analysis\"}]}\n]}\n<\/script>\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=DM+Serif+Display&family=Source+Sans+3:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500;600&display=swap\" 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Display',serif;font-size:32px;margin-bottom:12px;position:relative}\n.shop-cta p{font-size:17px;color:rgba(255,255,255,.7);margin-bottom:28px;max-width:700px;margin-left:auto;margin-right:auto;position:relative}\n.shop-cta .cta-btn{display:inline-flex;align-items:center;gap:8px;padding:14px 36px;background:var(--blue);color:#fff;text-decoration:none;border-radius:var(--radius-sm);font-weight:600;font-size:16px;transition:all .2s;position:relative}\n.shop-cta .cta-btn:hover{background:var(--blue-light);transform:translateY(-2px);box-shadow:0 8px 24px rgba(37,99,235,.3)}\n.page-footer{background:var(--beige);border-top:1px solid var(--beige-dark);padding:32px 0;text-align:center}\n.page-footer a{color:var(--blue);text-decoration:none;font-weight:500}.page-footer p{font-size:14px;color:var(--text-muted)}\n\n@media(max-width:1200px){.container,.hero-inner,.quick-nav-inner{padding:0 32px}.content-layout{grid-template-columns:1fr 280px;gap:32px}.calc-grid{grid-template-columns:1fr 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.formula-main{font-size:16px}.shop-cta h2{font-size:24px}}\n@media(max-width:480px){.hero h1{font-size:24px}.quick-nav a{padding:12px 12px;font-size:13px}.fault-grid{grid-template-columns:1fr}.units-grid{grid-template-columns:1fr}}\n@media print{.quick-nav,.shop-cta,.toc-sidebar,.demo-panel,.calc-panel{display:none}}\n<\/style>\n<\/head>\n<body>\n\n<header class=\"hero\">\n<div class=\"hero-inner\">\n<div class=\"breadcrumb\"><a href=\"https:\/\/vibromera.eu\/\">Home<\/a> \u2192 <a href=\"https:\/\/vibromera.eu\/glossary\/\">Glossary<\/a> \u2192 Vibration Analysis<\/div>\n<h1>Vibration Analysis \u2014 <span>Spectrum Diagnostics<\/span> Guide<\/h1>\n<div class=\"canon-badge\"><span style=\"font-size:14px;\">\ud83d\udccc<\/span> Canonical Reference Article \u2014 vibromera.eu<\/div>\n<p class=\"subtitle\">From FFT fundamentals to fault diagnosis: learn to read vibration spectrums, calculate bearing defect frequencies, assess severity per ISO 10816, and diagnose unbalance, misalignment, looseness, bearing and gear defects \u2014 with interactive tools and the Balanset-1A.<\/p>\n<\/div>\n<\/header>\n\n<nav class=\"quick-nav\"><div class=\"quick-nav-inner\">\n<a href=\"#calculators\">\ud83e\uddee Calculators<\/a>\n<a href=\"#fft-demo\">\ud83d\udcca FFT Demo<\/a>\n<a href=\"#fault-table\">\ud83d\udd0d Fault Table<\/a>\n<a href=\"#fundamentals\">\ud83d\udcd0 FFT Basics<\/a>\n<a href=\"#units\">\ud83d\udcca Units<\/a>\n<a href=\"#measurement\">\ud83d\udccf Measurement<\/a>\n<a href=\"#unbalance\">\u2696 Unbalance<\/a>\n<a href=\"#misalignment\">\ud83d\udd27 Misalignment<\/a>\n<a href=\"#looseness\">\ud83d\udd29 Looseness<\/a>\n<a href=\"#bearings\">\ud83d\udd35 Bearings<\/a>\n<a href=\"#gears\">\u2699 Gears<\/a>\n<a href=\"#belt\">\ud83d\udd17 Belts<\/a>\n<a href=\"#cavitation\">\ud83d\udca7 Cavitation<\/a>\n<a href=\"#oilwhirl\">\ud83c\udf00 Oil Whirl<\/a>\n<a href=\"#phase\">\ud83e\udded Phase<\/a>\n<a href=\"#envelope\">\ud83d\udce1 Envelope<\/a>\n<a href=\"#iso-full\">\ud83d\udccb ISO 10816<\/a>\n<a href=\"#monitoring\">\ud83d\udcc8 Monitoring<\/a>\n<a href=\"#faq\">\u2753 FAQ<\/a>\n<\/div><\/nav>\n\n\n<section class=\"section-bg\" id=\"calculators\">\n<div class=\"container\">\n<div class=\"section-header\">\n<h2>Interactive Diagnostic Calculators<\/h2>\n<p>Essential tools for vibration analysis \u2014 bearing defect frequencies, gear mesh frequency, severity assessment, and unit conversion<\/p>\n<\/div>\n<div class=\"calc-grid\">\n\n\n<div class=\"calc-panel\">\n<div class=\"calc-header\">\ud83d\udd35 Bearing Defect Frequency Calculator<\/div>\n<div class=\"calc-body\">\n<div class=\"calc-form\" id=\"bearing-calc-form\">\n<div>\n<label>Quick Select \u2014 Common Bearing<\/label>\n<select id=\"bc-preset\" onchange=\"applyBearingPreset()\">\n<option value=\"\">\u2014 Manual entry \u2014<\/option>\n<optgroup label=\"62xx Series (Light)\">\n<option value=\"9,7.938,38.5,0\">6200 \u2014 9 balls, Bd 7.94, Pd 38.5<\/option>\n<option value=\"7,7.938,25.4,0\">6201 \u2014 7 balls, Bd 7.94, Pd 25.4<\/option>\n<option value=\"8,7.938,32.0,0\">6202 \u2014 8 balls, Bd 7.94, Pd 32.0<\/option>\n<option value=\"8,9.525,34.0,0\">6203 \u2014 8 balls, Bd 9.53, Pd 34.0<\/option>\n<option value=\"8,7.938,33.5,0\">6204 \u2014 8 balls, Bd 7.94, Pd 33.5<\/option>\n<option value=\"9,7.938,38.5,0\">6205 \u2014 9 balls, Bd 7.94, Pd 38.5<\/option>\n<option value=\"9,9.525,46.0,0\">6206 \u2014 9 balls, Bd 9.53, Pd 46.0<\/option>\n<option value=\"8,11.112,53.5,0\">6207 \u2014 8 balls, Bd 11.11, Pd 53.5<\/option>\n<option value=\"9,11.906,60.0,0\">6208 \u2014 9 balls, Bd 11.91, Pd 60.0<\/option>\n<option value=\"8,12.7,65.0,0\">6209 \u2014 8 balls, Bd 12.70, Pd 65.0<\/option>\n<option value=\"10,12.7,70.0,0\">6210 \u2014 10 balls, Bd 12.70, Pd 70.0<\/option>\n<\/optgroup>\n<optgroup label=\"63xx Series (Medium)\">\n<option value=\"7,11.112,34.85,0\">6305 \u2014 7 balls, Bd 11.11, Pd 34.9<\/option>\n<option value=\"8,11.509,43.5,0\">6306 \u2014 8 balls, Bd 11.51, Pd 43.5<\/option>\n<option value=\"8,13.494,50.0,0\">6307 \u2014 8 balls, Bd 13.49, Pd 50.0<\/option>\n<option value=\"8,15.081,58.5,0\">6308 \u2014 8 balls, Bd 15.08, Pd 58.5<\/option>\n<option value=\"8,17.462,65.0,0\">6309 \u2014 8 balls, Bd 17.46, Pd 65.0<\/option>\n<option value=\"8,19.05,72.5,0\">6310 \u2014 8 balls, Bd 19.05, Pd 72.5<\/option>\n<\/optgroup>\n<optgroup label=\"NU \/ NJ Series (Cylindrical Roller)\">\n<option value=\"13,9.0,42.5,0\">NU 205 \u2014 13 rollers, Bd 9.0, Pd 42.5<\/option>\n<option value=\"12,10.0,52.0,0\">NU 206 \u2014 12 rollers, Bd 10.0, Pd 52.0<\/option>\n<option value=\"14,10.0,52.0,0\">NU 208 \u2014 14 rollers, Bd 10.0, Pd 52.0<\/option>\n<\/optgroup>\n<optgroup label=\"Tapered Roller\">\n<option value=\"17,8.73,45.5,14\">30205 \u2014 17 rollers, Bd 8.73, Pd 45.5, \u03b1 14\u00b0<\/option>\n<option value=\"17,10.4,54.5,14\">30206 \u2014 17 rollers, Bd 10.4, Pd 54.5, \u03b1 14\u00b0<\/option>\n<option value=\"17,12.15,63.0,14\">30208 \u2014 17 rollers, Bd 12.15, Pd 63.0, \u03b1 14\u00b0<\/option>\n<\/optgroup>\n<\/select>\n<\/div>\n<div class=\"calc-row\">\n<div><label>Shaft Speed (RPM)<\/label><input type=\"number\" id=\"bc-rpm\" value=\"1500\" min=\"1\"><\/div>\n<div><label>Number of Rolling Elements (n)<\/label><input type=\"number\" id=\"bc-balls\" value=\"9\" min=\"2\"><\/div>\n<\/div>\n<div class=\"calc-row\">\n<div><label>Ball \/ Roller Diameter, Bd (mm)<\/label><input type=\"number\" id=\"bc-bd\" value=\"7.938\" step=\"0.001\" min=\"0.1\"><\/div>\n<div><label>Pitch Diameter, Pd (mm)<\/label><input type=\"number\" id=\"bc-pd\" value=\"38.5\" step=\"0.1\" min=\"1\"><\/div>\n<\/div>\n<div><label>Contact Angle, \u03b1 (degrees)<\/label><input type=\"number\" id=\"bc-angle\" value=\"0\" min=\"0\" max=\"45\" step=\"1\"><\/div>\n<button class=\"calc-btn\" onclick=\"calcBearing()\">Calculate Bearing Frequencies<\/button>\n<\/div>\n<div class=\"results-panel\" id=\"bc-results\">\n<div class=\"result-grid\">\n<div class=\"result-card\"><div class=\"r-label\">BPFO \u2014 Outer Race<\/div><div class=\"r-value\" id=\"bc-bpfo\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">BPFI \u2014 Inner Race<\/div><div class=\"r-value\" id=\"bc-bpfi\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">BSF \u2014 Ball\/Roller Spin<\/div><div class=\"r-value\" id=\"bc-bsf\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">FTF \u2014 Cage (Train)<\/div><div class=\"r-value\" id=\"bc-ftf\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<\/div>\n<div style=\"margin-top:12px;font-size:12px;color:var(--text-muted);text-align:center;\">1\u00d7 shaft = <span id=\"bc-1x\">\u2014<\/span> Hz | BPFO\/BPFI ratio: <span id=\"bc-ratio\">\u2014<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n<div class=\"calc-panel\">\n<div class=\"calc-header\">\ud83d\udccf ISO 10816 Severity & RPM\u2194Hz & GMF<\/div>\n<div class=\"calc-body\">\n\n<div class=\"calc-form\">\n<div class=\"calc-row\">\n<div><label>Vibration Velocity (mm\/s RMS)<\/label><input type=\"number\" id=\"sev-vel\" value=\"4.5\" step=\"0.1\" min=\"0\"><\/div>\n<div><label>Machine Class<\/label><select id=\"sev-class\">\n<option value=\"1\">Class I \u2014 Small (\u2264 15 kW)<\/option>\n<option value=\"2\" selected>Class II \u2014 Medium (15\u201375 kW)<\/option>\n<option value=\"3\">Class III \u2014 Large, rigid foundation<\/option>\n<option value=\"4\">Class IV \u2014 Large, flexible foundation<\/option>\n<\/select><\/div>\n<\/div>\n<button class=\"calc-btn\" onclick=\"calcSeverity()\">Assess Severity<\/button>\n<\/div>\n<div class=\"severity-bar\"><div class=\"sev-zone sev-a\">A Good<\/div><div class=\"sev-zone sev-b\">B Acceptable<\/div><div class=\"sev-zone sev-c\">C Alert<\/div><div class=\"sev-zone sev-d\">D Danger<\/div><\/div>\n<div id=\"sev-result\" class=\"severity-result\" style=\"display:none;\"><\/div>\n\n<hr style=\"margin:20px 0;border:none;border-top:1px solid var(--border-light);\">\n\n<div style=\"font-weight:700;font-size:14px;color:var(--navy);margin-bottom:10px;\">\ud83d\udd04 RPM \u2194 Hz Converter<\/div>\n<div class=\"calc-form\">\n<div class=\"calc-row\">\n<div><label>RPM<\/label><input type=\"number\" id=\"conv-rpm\" value=\"1500\" min=\"0\" oninput=\"convRPM()\"><\/div>\n<div><label>Frequency (Hz)<\/label><input type=\"number\" id=\"conv-hz\" value=\"25\" step=\"0.01\" min=\"0\" oninput=\"convHz()\"><\/div>\n<\/div>\n<\/div>\n<div style=\"margin-top:8px;font-size:13px;color:var(--text-muted);text-align:center;\">1\u00d7 = <span id=\"conv-1x\">25.00<\/span> Hz | 2\u00d7 = <span id=\"conv-2x\">50.00<\/span> Hz | 3\u00d7 = <span id=\"conv-3x\">75.00<\/span> Hz | Period = <span id=\"conv-period\">40.00<\/span> ms<\/div>\n\n<hr style=\"margin:20px 0;border:none;border-top:1px solid var(--border-light);\">\n\n<div style=\"font-weight:700;font-size:14px;color:var(--navy);margin-bottom:10px;\">\u2699\ufe0f Gear Mesh Frequency (GMF)<\/div>\n<div class=\"calc-form\">\n<div class=\"calc-row\">\n<div><label>Shaft RPM (driving gear)<\/label><input type=\"number\" id=\"gmf-rpm\" value=\"1500\" min=\"1\"><\/div>\n<div><label>Number of Teeth (driving gear)<\/label><input type=\"number\" id=\"gmf-teeth1\" value=\"20\" min=\"1\"><\/div>\n<\/div>\n<div><label>Number of Teeth (driven gear) \u2014 optional, for gear ratio<\/label><input type=\"number\" id=\"gmf-teeth2\" value=\"60\" min=\"1\"><\/div>\n<button class=\"calc-btn\" onclick=\"calcGMF()\">Calculate GMF<\/button>\n<\/div>\n<div class=\"results-panel\" id=\"gmf-results\">\n<div class=\"result-grid\">\n<div class=\"result-card primary\"><div class=\"r-label\">Gear Mesh Frequency (GMF)<\/div><div class=\"r-value\" id=\"gmf-val\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">2\u00d7 GMF<\/div><div class=\"r-value\" id=\"gmf-2x\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">3\u00d7 GMF<\/div><div class=\"r-value\" id=\"gmf-3x\">\u2014<\/div><div class=\"r-unit\">Hz<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">Gear Ratio<\/div><div class=\"r-value\" id=\"gmf-ratio\">\u2014<\/div><div class=\"r-unit\">:1<\/div><\/div>\n<div class=\"result-card\"><div class=\"r-label\">Driven Shaft Speed<\/div><div class=\"r-value\" id=\"gmf-driven\">\u2014<\/div><div class=\"r-unit\">RPM<\/div><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n<section class=\"section-bg alt\" id=\"fault-table\">\n<div class=\"container\">\n<div class=\"section-header\">\n<h2>Fault Identification at a Glance<\/h2>\n<p>Each mechanical fault produces a characteristic \"fingerprint\" in the vibration spectrum<\/p>\n<\/div>\n<div class=\"fault-grid\">\n<div class=\"fault-card f-unbal\"><div class=\"fc-icon\">\u2696\ufe0f<\/div><div class=\"fc-name\">Unbalance<\/div><div class=\"fc-freq unbal\">1\u00d7<\/div><div class=\"fc-desc\">Dominant peak at shaft speed. Radial. Amplitude \u221d speed\u00b2. Stable phase.<\/div><\/div>\n<div class=\"fault-card f-misal\"><div class=\"fc-icon\">\ud83d\udd27<\/div><div class=\"fc-name\">Misalignment<\/div><div class=\"fc-freq misal\">2\u00d7 (+ 1\u00d7, 3\u00d7)<\/div><div class=\"fc-desc\">Strong 2nd harmonic. High axial. 180\u00b0 phase across coupling.<\/div><\/div>\n<div class=\"fault-card f-loose\"><div class=\"fc-icon\">\ud83d\udd29<\/div><div class=\"fc-name\">Looseness<\/div><div class=\"fc-freq loose\">1\u00d7,2\u00d7,3\u00d7\u2026n\u00d7<\/div><div class=\"fc-desc\">\"Forest\" of harmonics. May show 0.5\u00d7 subharmonics.<\/div><\/div>\n<div class=\"fault-card f-bear\"><div class=\"fc-icon\">\ud83d\udd35<\/div><div class=\"fc-name\">Bearing Defect<\/div><div class=\"fc-freq bear\">BPFO\/BPFI\/BSF<\/div><div class=\"fc-desc\">Non-synchronous peaks. Sidebands at 1\u00d7. Noise floor rise.<\/div><\/div>\n<div class=\"fault-card f-gear\"><div class=\"fc-icon\">\u2699\ufe0f<\/div><div class=\"fc-name\">Gear Fault<\/div><div class=\"fc-freq gear\">GMF \u00b1 1\u00d7<\/div><div class=\"fc-desc\">Gear mesh frequency with sidebands at shaft speed.<\/div><\/div>\n<\/div>\n\n<div class=\"table-wrap\">\n<div class=\"table-title\">\ud83d\udcca Complete Diagnostic Reference Table<\/div><style id=\"vbm-diag-tablefix\">.table-scroll table td:first-child,.table-scroll table th:first-child{min-width:140px;word-break:normal;overflow-wrap:normal;hyphens:none}<\/style>\n<div class=\"table-scroll\"><table>\n<thead><tr><th>Fault<\/th><th>Primary Frequency<\/th><th>Harmonics<\/th><th>Direction<\/th><th>Phase Behaviour<\/th><th>Key Distinguishing Feature<\/th><\/tr><\/thead>\n<tbody>\n<tr><td><strong>Static unbalance<\/strong><\/td><td class=\"mono\">1\u00d7<\/td><td>Low \/ none<\/td><td>Radial (H,V)<\/td><td>In-phase both bearings<\/td><td>Pure 1\u00d7 sinusoid. Amplitude \u221d \u03c9\u00b2.<\/td><\/tr>\n<tr><td><strong>Dynamic unbalance<\/strong><\/td><td class=\"mono\">1\u00d7<\/td><td>Low \/ none<\/td><td>Radial (H,V)<\/td><td>~180\u00b0 between bearings<\/td><td>1\u00d7 dominant, bearings out of phase (couple).<\/td><\/tr>\n<tr><td><strong>Parallel misalignment<\/strong><\/td><td class=\"mono\">2\u00d7 (\u2265 1\u00d7)<\/td><td>1\u00d7, 3\u00d7<\/td><td>Radial<\/td><td>180\u00b0 across coupling<\/td><td>2\u00d7 often > 1\u00d7. High radial at coupling.<\/td><\/tr>\n<tr><td><strong>Angular misalignment<\/strong><\/td><td class=\"mono\">1\u00d7, 2\u00d7<\/td><td>3\u00d7<\/td><td>Axial dominant<\/td><td>180\u00b0 across coupling (axial)<\/td><td>High axial. Axial \u2265 50% of radial.<\/td><\/tr>\n<tr><td><strong>Component looseness<\/strong><\/td><td class=\"mono\">1\u00d7,2\u00d7\u202610\u00d7+<\/td><td>Many (~10\u00d7)<\/td><td>Radial<\/td><td>Erratic<\/td><td>\"Forest\" of harmonics. Possible 0.5\u00d7 sub.<\/td><\/tr>\n<tr><td><strong>Structural looseness<\/strong><\/td><td class=\"mono\">1\u00d7 or 2\u00d7<\/td><td>Few above 2\u00d7<\/td><td>Vertical<\/td><td>Unstable<\/td><td>Strong vertical. Responds to bolt check.<\/td><\/tr>\n<tr><td><strong>Outer race (BPFO)<\/strong><\/td><td class=\"mono\">BPFO, 2\u00d7BPFO\u2026<\/td><td>Multiple BPFO<\/td><td>Radial<\/td><td>N\/A<\/td><td>Non-synchronous. No 1\u00d7 sidebands.<\/td><\/tr>\n<tr><td><strong>Inner race (BPFI)<\/strong><\/td><td class=\"mono\">BPFI, 2\u00d7BPFI\u2026<\/td><td>Multiple BPFI<\/td><td>Radial<\/td><td>Modulated at 1\u00d7<\/td><td>BPFI harmonics with \u00b11\u00d7 sidebands.<\/td><\/tr>\n<tr><td><strong>Rolling element (BSF)<\/strong><\/td><td class=\"mono\">BSF, 2\u00d7BSF\u2026<\/td><td>Multiple BSF<\/td><td>Radial<\/td><td>N\/A<\/td><td>2\u00d7BSF often > 1\u00d7BSF. Non-synchronous.<\/td><\/tr>\n<tr><td><strong>Cage (FTF)<\/strong><\/td><td class=\"mono\">FTF \u2248 0.4\u00d7<\/td><td>2,3\u00d7 FTF<\/td><td>Radial<\/td><td>N\/A<\/td><td>Sub-synchronous (< 1\u00d7).<\/td><\/tr>\n<tr><td><strong>Gear mesh<\/strong><\/td><td class=\"mono\">GMF=N\u00d71\u00d7<\/td><td>2,3\u00d7 GMF<\/td><td>Radial+axial<\/td><td>Modulated at 1\u00d7<\/td><td>GMF with sidebands. N = teeth.<\/td><\/tr>\n<tr><td><strong>Electrical (motor)<\/strong><\/td><td class=\"mono\">2\u00d7 line freq<\/td><td>\u2014<\/td><td>Radial<\/td><td>Drops on power-off<\/td><td>100\/120 Hz. Instant drop test.<\/td><\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n<section class=\"section-bg white\" id=\"fft-demo\">\n<div class=\"container\">\n<div class=\"demo-panel\">\n<h3>Interactive FFT Spectrum Demonstration \u2014 16 Fault Scenarios<\/h3>\n<p style=\"text-align:center;color:var(--text-secondary);margin-bottom:20px;font-size:14px;\">Select a fault type to see characteristic time waveform and frequency spectrum. Compare patterns to identify the root cause.<\/p>\n\n<div class=\"demo-categories\">\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Baseline<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn active\" data-fault=\"normal\">\u2705 Normal<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Unbalance<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"unbal_static\">\u2696\ufe0f Static<\/button>\n<button class=\"demo-btn\" data-fault=\"unbal_dynamic\">\u2696\ufe0f Dynamic<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Misalignment<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"misal_parallel\">\ud83d\udd27 Parallel<\/button>\n<button class=\"demo-btn\" data-fault=\"misal_angular\">\ud83d\udd27 Angular<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Looseness<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"loose_component\">\ud83d\udd29 Component<\/button>\n<button class=\"demo-btn\" data-fault=\"loose_structural\">\ud83d\udd29 Structural<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Bearings<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"bear_outer\">\ud83d\udd35 BPFO<\/button>\n<button class=\"demo-btn\" data-fault=\"bear_inner\">\ud83d\udd35 BPFI<\/button>\n<button class=\"demo-btn\" data-fault=\"bear_rolling\">\ud83d\udd35 BSF<\/button>\n<button class=\"demo-btn\" data-fault=\"bear_cage\">\ud83d\udd35 FTF<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Gears<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"gear_healthy\">\u2699\ufe0f Healthy<\/button>\n<button class=\"demo-btn\" data-fault=\"gear_worn\">\u2699\ufe0f Worn<\/button>\n<\/div>\n<\/div>\n\n<div class=\"demo-cat\">\n<div class=\"demo-cat-label\">Other<\/div>\n<div class=\"demo-cat-btns\">\n<button class=\"demo-btn\" data-fault=\"electrical\">\u26a1 Electrical<\/button>\n<button class=\"demo-btn\" data-fault=\"belt\">\ud83d\udd17 Belt<\/button>\n<button class=\"demo-btn\" data-fault=\"cavitation\">\ud83d\udca7 Cavitation<\/button>\n<button class=\"demo-btn\" data-fault=\"oilwhirl\">\ud83c\udf00 Oil Whirl<\/button>\n<\/div>\n<\/div>\n\n<\/div>\n\n<div class=\"demo-desc\" id=\"demo-desc\">Normal operating condition \u2014 low, stable vibration. Small 1\u00d7 peak from residual unbalance. Clean spectrum.<\/div>\n<div class=\"demo-charts\">\n<div class=\"chart-box\"><h4>Time Domain (Waveform)<\/h4><canvas id=\"demo-time\"><\/canvas><\/div>\n<div class=\"chart-box\"><h4>Frequency Spectrum (FFT)<\/h4><canvas id=\"demo-fft\"><\/canvas><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n\n\n<main class=\"main-content\" id=\"fundamentals\">\n<div class=\"container\">\n<div class=\"content-layout\">\n<article class=\"article-content\">\n\n<h2>What is Vibration Analysis?<\/h2>\n<div class=\"info-box\" style=\"border-left-color:var(--navy);background:var(--beige-light);\">\n<div class=\"box-title\" style=\"font-size:16px;\">Quick Answer<\/div>\n<p style=\"font-size:15px;\"><strong>Vibration analysis<\/strong> is the process of measuring and interpreting mechanical oscillations of rotating machinery to diagnose faults without disassembly. Using <strong>FFT<\/strong> (Fast Fourier Transform), the complex vibration signal is decomposed into individual frequency components. Each fault produces a characteristic spectral \"fingerprint\": <a href=\"https:\/\/vibromera.eu\/glossary\/unbalance\/\">unbalance<\/a> at 1\u00d7 RPM, <a href=\"https:\/\/vibromera.eu\/glossary\/misalignment\/\">misalignment<\/a> at 2\u00d7, looseness as multiple harmonics, bearing defects at non-synchronous frequencies. The <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\">Balanset-1A<\/a> performs both balancing and spectrum analysis in one portable instrument.<\/p>\n<\/div>\n<p>Every rotating machine vibrates. In a healthy machine, vibration is low and stable \u2014 its normal \"operating signature.\" As defects develop, vibration changes in predictable ways. By measuring and analysing these changes, we can identify the root cause, predict failure, and schedule maintenance before catastrophic breakdown. This is the foundation of <strong>predictive maintenance<\/strong>.<\/p>\n\n<h2>FFT: The Core of Spectrum Analysis<\/h2>\n<p>A vibration sensor (accelerometer) converts mechanical oscillation into an electrical signal. Displayed over time, this is the <strong>waveform<\/strong> \u2014 a complex, seemingly chaotic curve when multiple faults are present. FFT (Fast Fourier Transform) decomposes this complex signal into individual sinusoidal components, each with its own frequency and amplitude.<\/p>\n<p>Think of FFT as a prism splitting white light into a rainbow. The complex waveform is \"white light\" \u2014 FFT reveals the individual \"colours\" (frequencies) hidden inside. The result is the <strong>vibration spectrum<\/strong> \u2014 the primary diagnostic tool.<\/p>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Rotational Frequency<\/div>\n<div class=\"formula-main\">f\u2081\u2093 = RPM \/ 60 (Hz)<\/div>\n<div class=\"formula-note\">1\u00d7 = shaft rotational frequency \u2014 the reference for all spectral analysis<\/div>\n<\/div>\n\n<h3>Key Spectrum Parameters<\/h3>\n<ul>\n<li><strong>Frequency (X-axis, Hz):<\/strong> How often oscillations occur. Directly linked to the source. 1\u00d7 = shaft speed. 2\u00d7 = twice shaft speed.<\/li>\n<li><strong>Amplitude (Y-axis, mm\/s RMS):<\/strong> Vibration intensity at each frequency. Higher peaks = more energy = more serious condition.<\/li>\n<li><strong>Harmonics:<\/strong> Integer multiples of the fundamental: 2\u00d7 (2nd), 3\u00d7 (3rd), 4\u00d7, etc. Their presence and relative height carry diagnostic information.<\/li>\n<li><strong>Phase (\u00b0):<\/strong> Timing relationship at different measurement points. Essential for distinguishing unbalance (in-phase) from misalignment (180\u00b0).<\/li>\n<\/ul>\n\n\n<h2 id=\"units\">Vibration Measurement Units: Displacement, Velocity, Acceleration<\/h2>\n<p>Vibration can be measured as three different physical parameters. Each emphasises different frequency ranges, making them suited to different diagnostic tasks. Understanding when to use which parameter is fundamental to effective analysis.<\/p>\n\n<div class=\"units-grid\">\n<div class=\"unit-card disp\">\n<h4>\ud83d\udccf Displacement<\/h4>\n<div class=\"u-param\">\u00b5m (peak-to-peak) or mil<\/div>\n<div class=\"u-range\">Best range: <strong>1\u2013100 Hz<\/strong><\/div>\n<p>Measures how <em>far<\/em> the surface moves. Emphasises low frequencies \u2014 ideal for slow-speed machines, shaft orbit analysis, and proximity probes on journal bearings. 1 mil = 25.4 \u00b5m.<\/p>\n<\/div>\n<div class=\"unit-card vel\">\n<h4>\ud83d\udcc8 Velocity<\/h4>\n<div class=\"u-param\">mm\/s (RMS)<\/div>\n<div class=\"u-range\">Best range: <strong>10\u20131000 Hz<\/strong><\/div>\n<p>Measures how <em>fast<\/em> the surface moves. The <strong>standard parameter<\/strong> for general machinery monitoring per ISO 10816. Flat frequency response gives equal weight to most fault types. <strong>Balanset-1A measures in mm\/s RMS.<\/strong><\/p>\n<\/div>\n<div class=\"unit-card acc\">\n<h4>\ud83d\udca5 Acceleration<\/h4>\n<div class=\"u-param\">m\/s\u00b2 or g (RMS\/peak)<\/div>\n<div class=\"u-range\">Best range: <strong>500 Hz \u2013 20 kHz+<\/strong><\/div>\n<p>Measures the <em>force<\/em> of vibration. Emphasises high frequencies \u2014 ideal for early bearing defects, gear mesh, and impacts. 1 g = 9.81 m\/s\u00b2. Used for envelope\/demodulation analysis.<\/p>\n<\/div>\n<\/div>\n\n<div class=\"table-wrap\">\n<div class=\"table-title\">When to Use Each Parameter<\/div>\n<div class=\"table-scroll\"><table>\n<thead><tr><th>Parameter<\/th><th>Unit<\/th><th>Frequency Range<\/th><th>Best For<\/th><th>Standards<\/th><\/tr><\/thead>\n<tbody>\n<tr><td><strong>Displacement<\/strong><\/td><td class=\"mono\">\u00b5m pk-pk<\/td><td>1\u2013100 Hz<\/td><td>Slow machines (< 600 RPM), shaft orbit, proximity probes, journal bearings<\/td><td>ISO 7919 (shaft vibration)<\/td><\/tr>\n<tr><td><strong>Velocity<\/strong><\/td><td class=\"mono\">mm\/s RMS<\/td><td>10\u20131000 Hz<\/td><td><strong>General machinery monitoring<\/strong> \u2014 unbalance, misalignment, looseness. Default parameter.<\/td><td>ISO 10816, ISO 20816<\/td><\/tr>\n<tr><td><strong>Acceleration<\/strong><\/td><td class=\"mono\">g or m\/s\u00b2 RMS<\/td><td>500 Hz \u2013 20 kHz<\/td><td>Early bearing defects, gear mesh, impacts, high-speed machinery<\/td><td>ISO 15242 (bearing vibration)<\/td><\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Conversion at a Single Frequency<\/div>\n<div class=\"formula-main\" style=\"font-size:16px;\">v = 2\u03c0f \u00b7 d | a = 2\u03c0f \u00b7 v = (2\u03c0f)\u00b2 \u00b7 d<\/div>\n<div class=\"formula-note\">d = displacement (m), v = velocity (m\/s), a = acceleration (m\/s\u00b2), f = frequency (Hz)<\/div>\n<\/div>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udca1 Rule of Thumb<\/div>\n<p>If you have only one sensor and one parameter to choose \u2014 <strong>choose velocity (mm\/s RMS)<\/strong>. It covers the broadest range of common faults with flat response. The Balanset-1A uses this as its native parameter. Add acceleration measurement only when you need to catch early-stage bearing or gear defects at high frequencies.<\/p>\n<\/div>\n\n<h2 id=\"measurement\">Measurement Technique with Balanset-1A<\/h2>\n<h3>Sensor Placement<\/h3>\n<p>The quality of diagnosis depends entirely on measurement quality. Vibration forces are transmitted through bearings, so sensors must be mounted on bearing housings \u2014 as close to the bearing as possible, on the load-bearing structure (not covers or cooling fins).<\/p>\n<ul>\n<li><strong>Surface preparation:<\/strong> Clean, flat, free of paint flakes. Magnetic base must sit flush.<\/li>\n<li><strong>Radial horizontal (H):<\/strong> Perpendicular to shaft, horizontal plane. Often highest amplitude.<\/li>\n<li><strong>Radial vertical (V):<\/strong> Perpendicular to shaft, vertical plane.<\/li>\n<li><strong>Axial (A):<\/strong> Parallel to shaft. Critical for detecting misalignment.<\/li>\n<\/ul>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udca1 Two-Channel Diagnostic Trick<\/div>\n<p>The Balanset-1A has 2 channels. For diagnostics, mount both sensors on the <em>same<\/em> bearing \u2014 one radial, one axial. This gives simultaneous radial + axial spectrums, enabling instant misalignment detection.<\/p>\n<\/div>\n\n<h3>Balanset-1A Modes for Diagnostics<\/h3>\n<ul>\n<li><strong>F1 \u2014 Spectrum Analyser:<\/strong> Full FFT display. The primary diagnostic mode.<\/li>\n<li><strong>F5 \u2014 Vibrometer:<\/strong> Quick assessment. Compare V1s (total RMS) vs. V1o (1\u00d7). If V1s \u2248 V1o \u2192 unbalance. If V1s \u226b V1o \u2192 other faults.<\/li>\n<li><strong>F8 \u2014 Charts:<\/strong> Detailed spectrum + time waveform. Best for harmonic patterns and bearing frequencies.<\/li>\n<\/ul>\n\n<div class=\"info-box warning\">\n<div class=\"box-title\">\u26a0\ufe0f V1s vs. V1o \u2014 The First Diagnostic Check<\/div>\n<p>Before balancing, compare V1s with V1o. If V1s \u226b V1o (e.g., 8 vs. 2 mm\/s), most vibration is NOT from unbalance. Balancing won't solve it \u2014 examine the full spectrum.<\/p>\n<\/div>\n\n\n<h2 id=\"phase\">Phase Analysis \u2014 The Diagnostic Differentiator<\/h2>\n<p>Frequency tells you <em>what<\/em> is vibrating; phase tells you <em>how<\/em>. Two faults can produce identical spectrums (both dominated by 1\u00d7) \u2014 only phase analysis distinguishes them. Phase is the angular relationship between vibration at different measurement points, measured in degrees (0\u00b0\u2013360\u00b0).<\/p>\n\n<div class=\"table-wrap\">\n<div class=\"table-title\">\ud83e\udded Phase \u2192 Diagnosis Reference Table<\/div>\n<div class=\"table-scroll\"><table>\n<thead><tr><th>Phase Relationship<\/th><th>Measurement Points<\/th><th>Diagnosis<\/th><th>Explanation<\/th><\/tr><\/thead>\n<tbody>\n<tr><td class=\"mono\"><strong>0\u00b0 (in-phase)<\/strong><\/td><td>Bearing 1 \u2194 Bearing 2 (radial)<\/td><td><strong>Static unbalance<\/strong><\/td><td>Both bearings move together in sync \u2014 single heavy spot in centre of rotor. Single-plane correction.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~180\u00b0 (anti-phase)<\/strong><\/td><td>Bearing 1 \u2194 Bearing 2 (radial)<\/td><td><strong>Dynamic (couple) unbalance<\/strong><\/td><td>Bearings rock in opposition \u2014 two heavy spots at different planes create a rocking couple. Two-plane correction needed.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~90\u00b0<\/strong><\/td><td>Horizontal \u2194 Vertical (same bearing)<\/td><td><strong>Unbalance (any type)<\/strong><\/td><td>Normal for unbalance \u2014 force vector rotates with shaft, producing ~90\u00b0 between H and V at same point.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~180\u00b0<\/strong><\/td><td>Across coupling (radial)<\/td><td><strong>Parallel misalignment<\/strong><\/td><td>Coupling forces push shafts apart in opposite radial directions. 180\u00b0 across coupling with high 2\u00d7 is the signature.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>~180\u00b0<\/strong><\/td><td>Across coupling (axial)<\/td><td><strong>Angular misalignment<\/strong><\/td><td>Shafts alternately push\/pull axially. 180\u00b0 axial across coupling with high 1\u00d7 and 2\u00d7 is definitive.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>0\u00b0<\/strong><\/td><td>Across coupling (axial)<\/td><td><strong>Not misalignment<\/strong><\/td><td>Both sides moving same axial direction \u2014 likely thermal growth, piping strain, or soft foot. Not angular misalignment.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>Erratic \/ unstable<\/strong><\/td><td>Any consistent points<\/td><td><strong>Mechanical looseness<\/strong><\/td><td>Phase readings jump randomly between measurements \u2014 characteristic of impacts in loose joints. Unstable phase = looseness.<\/td><\/tr>\n<tr><td class=\"mono\"><strong>Slowly drifting<\/strong><\/td><td>Any point, over time<\/td><td><strong>Resonance or thermal effects<\/strong><\/td><td>Gradual phase shift during warmup suggests structural stiffness changing with temperature (thermal misalignment).<\/td><\/tr>\n<tr><td class=\"mono\"><strong>Consistent, non-0\/180\u00b0<\/strong><\/td><td>Bearing 1 \u2194 Bearing 2<\/td><td><strong>Combined static + couple unbalance<\/strong><\/td><td>Phase between 0\u00b0 and 180\u00b0 indicates a mix of static and couple components \u2014 requires two-plane balancing.<\/td><\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udca1 Phase Measurement with Balanset-1A<\/div>\n<p>The Balanset-1A displays phase at 1\u00d7 (the F1 value in vibrometer mode) using the tachometer as reference. To compare phase between two bearings, measure each bearing in the same direction (e.g., horizontal) with the tachometer on the same reference mark. The difference in phase readings reveals the fault type. No special software needed \u2014 just subtract the two readings.<\/p>\n<\/div>\n\n\n<h2 id=\"unbalance\">Fault 1: Unbalance<\/h2>\n<p><strong>Cause:<\/strong> Centre of mass displaced from rotation axis. Manufacturing tolerances, deposit buildup, erosion, broken blade, lost weight.<\/p>\n<p><strong>Spectrum:<\/strong> Dominant peak at exactly 1\u00d7 RPM. Very low harmonics. Radial vibration. Amplitude increases with speed\u00b2 (quadratic). Phase is stable and repeatable.<\/p>\n\n<h4>Static Unbalance (Single-Plane)<\/h4>\n<p>Pure 1\u00d7 peak, sinusoidal waveform. Both bearings in-phase. Single-plane correction.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-unbal-static\"><\/canvas><\/div>\n<div class=\"chart-caption\">Static unbalance \u2014 dominant 1\u00d7 at 25 Hz (1500 RPM). Minimal harmonics.<\/div>\n\n<h4>Dynamic Unbalance (Two-Plane \/ Couple)<\/h4>\n<p>Also 1\u00d7 dominant, but bearings ~180\u00b0 out of phase. Two-plane correction required.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-unbal-dynamic\"><\/canvas><\/div>\n<div class=\"chart-caption\">Dynamic unbalance \u2014 1\u00d7 dominant. Spectrum similar to static but phase differs at bearings.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Perform <a href=\"https:\/\/vibromera.eu\/glossary\/balancing\/\">rotor balancing<\/a> with the Balanset-1A. G-grade tolerance per <a href=\"https:\/\/vibromera.eu\/glossary\/iso-1940-1\/\">ISO 1940-1<\/a>.<\/p><\/div>\n\n<h2 id=\"misalignment\">Fault 2: Shaft Misalignment<\/h2>\n<p><strong>Cause:<\/strong> Axes of coupled shafts do not coincide. Can be parallel (offset) or angular (tilted), usually both.<\/p>\n\n<h4>Parallel Misalignment (Radial)<\/h4>\n<p>High 1\u00d7 and 2\u00d7 in the radial direction. 2\u00d7 often \u2265 1\u00d7. 180\u00b0 phase shift across coupling.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-misal-parallel\"><\/canvas><\/div>\n<div class=\"chart-caption\">Parallel misalignment \u2014 radial direction. Strong 1\u00d7 and 2\u00d7 with minor 3\u00d7.<\/div>\n\n<h4>Angular Misalignment \u2014 Radial<\/h4>\n<p>1\u00d7 and 2\u00d7 present in radial, but 2\u00d7 typically dominates.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-misal-angular-r\"><\/canvas><\/div>\n<div class=\"chart-caption\">Angular misalignment \u2014 radial (R). 2\u00d7 > 1\u00d7.<\/div>\n\n<h4>Angular Misalignment \u2014 Axial<\/h4>\n<p>Axial vibration \u2265 50% of radial. 180\u00b0 phase across coupling in axial. This is the key distinguishing measurement.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-misal-angular-a\"><\/canvas><\/div>\n<div class=\"chart-caption\">Angular misalignment \u2014 axial (A). Very high 2\u00d7 in axial direction.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Balancing will NOT help. Stop the machine and perform shaft alignment. Re-check vibration after.<\/p><\/div>\n\n<h2 id=\"looseness\">Fault 3: Mechanical Looseness<\/h2>\n<p><strong>Cause:<\/strong> Loss of structural stiffness \u2014 loose bolts, cracks in foundation, worn bearing seats, excessive clearances.<\/p>\n\n<h4>Component Looseness<\/h4>\n<p>\"Forest\" of harmonics \u2014 1\u00d7, 2\u00d7, 3\u00d7, 4\u00d7\u2026 up to 10\u00d7+ with decreasing amplitude. May show 0.5\u00d7 subharmonics.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-loose-component\"><\/canvas><\/div>\n<div class=\"chart-caption\">Component looseness \u2014 many harmonics 1\u00d7 through 10\u00d7. Note 0.5\u00d7 subharmonic.<\/div>\n\n<h4>Structural Looseness<\/h4>\n<p>1\u00d7 and\/or 2\u00d7 dominant. Few higher harmonics. Strong vertical vibration.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-loose-structural\"><\/canvas><\/div>\n<div class=\"chart-caption\">Structural looseness \u2014 1\u00d7 and 2\u00d7 dominate. Minimal higher harmonics.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Inspect and tighten mounting bolts. Check foundation. Always check looseness <em>before<\/em> balancing.<\/p><\/div>\n\n<h2 id=\"bearings\">Fault 4: Rolling Bearing Defects<\/h2>\n<p><strong>Cause:<\/strong> Pitting, spalling, wear on raceways, rolling elements, or cage.<\/p>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Bearing Defect Frequencies<\/div>\n<div class=\"formula-main\" style=\"font-size:16px;line-height:2;\">\nBPFO = (n\/2)(1 \u2212 Bd\/Pd\u00b7cos \u03b1) \u00b7 f<sub>s<\/sub><br>\nBPFI = (n\/2)(1 + Bd\/Pd\u00b7cos \u03b1) \u00b7 f<sub>s<\/sub><br>\nBSF = (Pd\/2Bd)(1 \u2212 (Bd\/Pd\u00b7cos \u03b1)\u00b2) \u00b7 f<sub>s<\/sub><br>\nFTF = \u00bd(1 \u2212 Bd\/Pd\u00b7cos \u03b1) \u00b7 f<sub>s<\/sub>\n<\/div>\n<div class=\"formula-note\">n = rolling elements | Bd = ball dia | Pd = pitch dia | \u03b1 = contact angle | f<sub>s<\/sub> = RPM\/60<\/div>\n<\/div>\n\n<h4>Outer Race Defect (BPFO)<\/h4>\n<p>Series of peaks at BPFO, 2\u00d7BPFO, 3\u00d7BPFO\u2026 No 1\u00d7 sidebands (stationary ring). Most common bearing fault.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-outer\"><\/canvas><\/div>\n<div class=\"chart-caption\">Outer race defect \u2014 BPFO harmonics at non-synchronous frequencies. No sidebands.<\/div>\n\n<h4>Inner Race Defect (BPFI)<\/h4>\n<p>BPFI harmonics with \u00b11\u00d7 sidebands (rotating ring, load zone modulation). Sideband pattern is the key identifier.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-inner\"><\/canvas><\/div>\n<div class=\"chart-caption\">Inner race defect \u2014 BPFI harmonics with \u00b11\u00d7 sidebands (smaller peaks flanking main peaks).<\/div>\n\n<h4>Rolling Element Defect (BSF)<\/h4>\n<p>BSF harmonics. 2\u00d7BSF often dominant. Non-synchronous. Often accompanied by race damage.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-rolling\"><\/canvas><\/div>\n<div class=\"chart-caption\">Rolling element defect \u2014 BSF harmonics. Note 2\u00d7BSF is highest (two-element damage).<\/div>\n\n<h4>Cage Defect (FTF)<\/h4>\n<p>Sub-synchronous peaks (FTF \u2248 0.4\u00d7 shaft speed). Low frequency. Often accompanies other bearing damage.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-bear-cage\"><\/canvas><\/div>\n<div class=\"chart-caption\">Cage defect \u2014 FTF and harmonics below 1\u00d7 shaft speed (sub-synchronous).<\/div>\n\n<div class=\"info-box success\">\n<div class=\"box-title\">Bearing Defect Progression (4 Stages)<\/div>\n<p><strong>Stage 1 \u2014 Subsurface:<\/strong> Ultrasonic zone (> 5 kHz). Not visible on standard FFT. Detectable by spike energy \/ enveloping.<\/p>\n<p><strong>Stage 2 \u2014 Early defect:<\/strong> Bearing frequencies appear (BPFO, BPFI). Low amplitude. This is where Balanset-1A begins detection.<\/p>\n<p><strong>Stage 3 \u2014 Progressed:<\/strong> Multiple harmonics. Sidebands develop. Noise floor rises.<\/p>\n<p><strong>Stage 4 \u2014 Advanced:<\/strong> Broadband noise. Bearing frequencies may disappear into noise. Replacement urgent.<\/p>\n<\/div>\n\n\n<h3 id=\"envelope\">Envelope (Demodulation) Analysis \u2014 Early Bearing Detection<\/h3>\n<p>Standard FFT spectrum analysis detects bearing defects from Stage 2 onward. But in Stage 1, bearing impacts are too weak to appear above the noise floor. <strong>Envelope analysis<\/strong> (also called demodulation or high-frequency detection, HFD) extends detection to much earlier stages.<\/p>\n\n<h4>How It Works<\/h4>\n<p>When a rolling element hits a defect, it generates a short impact pulse that excites high-frequency structural resonances (typically 5\u201320 kHz). These resonances \"ring\" briefly at each impact. Envelope analysis works in three steps:<\/p>\n<ol>\n<li><strong>Band-pass filter:<\/strong> Isolate the high-frequency resonance band (e.g., 5\u201315 kHz) where the impacts ring.<\/li>\n<li><strong>Rectify and envelope:<\/strong> Extract the amplitude modulation pattern \u2014 the \"envelope\" that follows the peaks of the ringing.<\/li>\n<li><strong>FFT of the envelope:<\/strong> Apply FFT to the envelope signal. The result shows the <em>repetition rate<\/em> of impacts \u2014 which equals the bearing defect frequencies (BPFO, BPFI, BSF, FTF).<\/li>\n<\/ol>\n\n<div class=\"info-box\">\n<div class=\"box-title\">Why Envelope Detects Earlier<\/div>\n<p>In the raw spectrum, a weak impact at BPFO might produce 0.1 mm\/s \u2014 invisible among machine noise of 2 mm\/s. But that same impact excites a resonance at 8 kHz where there is no other vibration source. After demodulation, the BPFO repetition pattern emerges clearly from a clean background.<\/p>\n<\/div>\n\n<h4>Related Parameters<\/h4>\n<ul>\n<li><strong>Spike Energy (SE):<\/strong> Overall measurement of high-frequency impact energy. Scalar trending value. Good for \"go\/no-go\" screening.<\/li>\n<li><strong>gSE \/ HFD \/ PeakVue:<\/strong> Vendor-specific names for envelope-derived parameters. All based on the same principle.<\/li>\n<li><strong>Acceleration enveloping:<\/strong> The Balanset-1A measures in velocity (mm\/s). For full envelope analysis, a dedicated analyser with acceleration input and band-pass filtering capability is ideal. However, the Balanset-1A's FFT can still detect Stage 2+ bearing defects effectively in the standard velocity spectrum.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-envelope\"><\/canvas><\/div>\n<div class=\"chart-caption\">Envelope spectrum of inner race defect \u2014 BPFI harmonics emerge clearly from demodulated high-frequency signal. Compare with raw velocity spectrum where these may be hidden in noise.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Check lubrication. Plan bearing replacement. Increase monitoring frequency.<\/p><\/div>\n\n<h2 id=\"gears\">Fault 5: Gear Defects<\/h2>\n<p><strong>Cause:<\/strong> Worn, pitted, or broken teeth. Gear eccentricity. GMF = number of teeth \u00d7 shaft RPM \/ 60.<\/p>\n\n<h4>Gear Eccentricity<\/h4>\n<p>GMF with sidebands at \u00b11\u00d7 shaft speed. Gear's 1\u00d7 may also be elevated.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-gear-eccentric\"><\/canvas><\/div>\n<div class=\"chart-caption\">Gear eccentricity \u2014 GMF at 500 Hz with \u00b11\u00d7 sidebands. Elevated 1\u00d7.<\/div>\n\n<h4>Gear Tooth Wear \/ Damage<\/h4>\n<p>Multiple GMF harmonics with dense sidebands. Severity tracks with sideband count and amplitude.<\/p>\n<div class=\"chart-container\"><canvas id=\"ch-gear-wear\"><\/canvas><\/div>\n<div class=\"chart-caption\">Gear wear \u2014 GMF and 2\u00d7GMF with multiple sidebands at 1\u00d7 intervals.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Check gearbox oil for metallic particles. Schedule inspection. Monitor GMF sideband trend.<\/p><\/div>\n\n<h2 id=\"electrical\">Electrical Faults (Motors)<\/h2>\n<p>Electromagnetic faults produce vibration at <strong>2\u00d7 line frequency<\/strong> (100 Hz on 50 Hz grids, 120 Hz on 60 Hz). Critical test: vibration disappears <em>instantly<\/em> when power is cut. Mechanical faults decay gradually.<\/p>\n<ul>\n<li><strong>Stator eccentricity:<\/strong> 2\u00d7 line frequency, steady amplitude.<\/li>\n<li><strong>Rotor bar defects:<\/strong> Sidebands around line frequency at slip frequency intervals.<\/li>\n<li><strong>Soft foot:<\/strong> Vibration changes when individual motor feet are loosened.<\/li>\n<\/ul>\n\n\n<h2 id=\"belt\">Fault 7: Belt Drive Problems<\/h2>\n<p><strong>Cause:<\/strong> Worn, misaligned, or improperly tensioned belts. Belt drives generate vibration at the <strong>belt pass frequency<\/strong>, which is typically a sub-synchronous frequency (below 1\u00d7 shaft speed) since the belt is longer than the pulley circumference.<\/p>\n\n<div class=\"formula-box\">\n<div class=\"formula-label\">Belt Frequency<\/div>\n<div class=\"formula-main\" style=\"font-size:16px;\">f<sub>belt<\/sub> = (\u03c0 \u00b7 D \u00b7 RPM) \/ (60 \u00b7 L)<\/div>\n<div class=\"formula-note\">D = pulley diameter (m) | L = belt length (m) | RPM = pulley speed<br>Simplified: f<sub>belt<\/sub> = pulley circumference speed \/ belt length<\/div>\n<\/div>\n\n<h4>Common Belt Signatures<\/h4>\n<ul>\n<li><strong>Belt wear \/ defect:<\/strong> Peaks at belt frequency (f<sub>belt<\/sub>) and its harmonics (2\u00d7, 3\u00d7, 4\u00d7 f<sub>belt<\/sub>). These appear below 1\u00d7 shaft speed \u2014 sub-synchronous peaks are the key indicator.<\/li>\n<li><strong>Belt misalignment:<\/strong> Elevated axial vibration at 1\u00d7 and 2\u00d7 shaft speed. Similar to shaft misalignment but restricted to the belt-driven machine.<\/li>\n<li><strong>Improper tension:<\/strong> High 1\u00d7 vibration that changes dramatically with belt tension adjustment. Overtight belts increase bearing load; loose belts cause slapping and belt-frequency peaks.<\/li>\n<li><strong>Resonance:<\/strong> Belt natural frequency (belt \"flutter\") can be excited if belt span resonance coincides with operating speed. Visible as broad peak at belt natural frequency.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-belt\"><\/canvas><\/div>\n<div class=\"chart-caption\">Belt drive defect \u2014 sub-synchronous peaks at belt frequency and harmonics (below 1\u00d7 shaft speed at 25 Hz).<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Check belt condition, tension, and pulley alignment. Replace worn belts. For recurring issues, verify pulley alignment with a laser tool or straight-edge.<\/p><\/div>\n\n\n<h2 id=\"cavitation\">Fault 8: Pump Cavitation<\/h2>\n<p><strong>Cause:<\/strong> Vapor bubbles form and collapse violently when local pressure drops below the liquid's vapor pressure \u2014 typically at the pump suction. Each bubble collapse creates a micro-impact. Thousands of collapses per second generate a characteristic broadband noise.<\/p>\n\n<h4>Spectral Signature<\/h4>\n<ul>\n<li><strong>Broadband high-frequency energy:<\/strong> Unlike mechanical faults (which produce discrete peaks), cavitation generates a raised noise floor across a wide frequency range, typically above 2\u20135 kHz. The spectrum looks like a \"hump\" or elevated plateau rather than sharp peaks.<\/li>\n<li><strong>Random, non-periodic:<\/strong> No harmonics, no relationship to shaft speed. The noise sounds like \"gravel\" or \"crackling\" \u2014 audible even without instruments.<\/li>\n<li><strong>Low-frequency effects:<\/strong> Severe cavitation may also cause instability at 1\u00d7 and broadband low-frequency noise from flow turbulence.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-cavitation\"><\/canvas><\/div>\n<div class=\"chart-caption\">Pump cavitation \u2014 broadband high-frequency noise (raised floor above 200 Hz). No discrete peaks \u2014 contrast with bearing defects which show specific frequencies.<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> Increase suction pressure (lower pump, open suction valve, reduce suction pipe losses). Check NPSH<sub>available<\/sub> vs. NPSH<sub>required<\/sub>. Reduce pump speed if possible. Cavitation causes rapid erosion damage \u2014 do not ignore.<\/p><\/div>\n\n\n<h2 id=\"oilwhirl\">Fault 9: Oil Whirl & Oil Whip (Journal Bearings)<\/h2>\n<p><strong>Cause:<\/strong> Fluid-film instability in journal (sleeve) bearings. The oil film wedge forces the shaft to orbit within the bearing clearance at a sub-synchronous frequency. This is distinct from rolling element bearing defects and occurs only in plain\/journal bearings.<\/p>\n\n<h4>Oil Whirl<\/h4>\n<ul>\n<li><strong>Frequency:<\/strong> Approximately <strong>0.42\u00d7 to 0.48\u00d7<\/strong> shaft speed (often cited as ~0.43\u00d7). This is a sub-synchronous peak that tracks shaft speed \u2014 if RPM increases, the whirl frequency increases proportionally.<\/li>\n<li><strong>Spectrum:<\/strong> A single peak at ~0.43\u00d7 that shifts with speed. Amplitude may be moderate.<\/li>\n<li><strong>Condition:<\/strong> Precursor to oil whip. Usually not immediately destructive but indicates instability.<\/li>\n<\/ul>\n\n<h4>Oil Whip<\/h4>\n<ul>\n<li><strong>Frequency:<\/strong> Locks onto the rotor's first <a href=\"https:\/\/vibromera.eu\/glossary\/natural-frequency\/\">natural frequency<\/a> (critical speed). Unlike whirl, it does NOT track shaft speed \u2014 the frequency remains constant as RPM changes.<\/li>\n<li><strong>Spectrum:<\/strong> Large sub-synchronous peak at the rotor's first critical speed. Amplitude can be very high \u2014 destructive.<\/li>\n<li><strong>Condition:<\/strong> <strong>Dangerous.<\/strong> Immediate action required. Can lead to bearing wipe-out and shaft damage.<\/li>\n<\/ul>\n\n<div class=\"chart-container\"><canvas id=\"ch-oilwhirl\"><\/canvas><\/div>\n<div class=\"chart-caption\">Oil whirl \u2014 sub-synchronous peak at ~0.43\u00d7 shaft speed (\u2248 10.7 Hz for 1500 RPM). Distinct from 0.5\u00d7 looseness.<\/div>\n\n<div class=\"info-box warning\">\n<div class=\"box-title\">\u26a0\ufe0f Oil Whirl vs. Looseness \u2014 How to Distinguish<\/div>\n<p>Both produce sub-synchronous peaks, but: <strong>Oil whirl<\/strong> is at ~0.43\u00d7 (not exactly 0.5\u00d7) and tracks with speed. <strong>Looseness<\/strong> produces peaks at exactly 0.5\u00d7, 1.5\u00d7, 2.5\u00d7 and does not track with speed (stays at fixed fractions of 1\u00d7). Oil whirl only occurs in journal\/sleeve bearings \u2014 if the machine has rolling element bearings, it cannot be oil whirl.<\/p>\n<\/div>\n\n<div class=\"action-box\"><p><strong>Action:<\/strong> For oil whirl: check bearing clearance, oil viscosity, and load. Increase bearing loading or change oil viscosity. For oil whip: <strong>reduce speed immediately<\/strong> below the critical threshold. Consult a rotor dynamics specialist.<\/p><\/div>\n\n\n<h2 id=\"iso-full\">ISO 10816 Vibration Severity \u2014 Complete Classification Table<\/h2>\n<p>ISO 10816 (superseded by ISO 20816 but still widely referenced) defines vibration severity zones for four machine classes. Vibration is measured as velocity in mm\/s RMS on bearing housings. The table below shows all zone boundaries for all four classes \u2014 use it as a quick reference when evaluating measurements.<\/p>\n\n<div class=\"table-wrap\" style=\"overflow:visible;\">\n<div class=\"table-title\">\ud83d\udccb ISO 10816-3 Vibration Severity Zones \u2014 All Machine Classes (mm\/s RMS)<\/div>\n<div class=\"table-scroll\"><table style=\"text-align:center;\">\n<thead><tr>\n<th style=\"text-align:left;min-width:180px;\">Machine Class<\/th>\n<th style=\"background:#16a34a;color:#fff;min-width:100px;\">Zone A<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Good<\/span><\/th>\n<th style=\"background:#65a30d;color:#fff;min-width:100px;\">Zone B<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Acceptable<\/span><\/th>\n<th style=\"background:#d97706;color:#fff;min-width:100px;\">Zone C<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Alert<\/span><\/th>\n<th style=\"background:#dc2626;color:#fff;min-width:100px;\">Zone D<br><span style=\"font-weight:400;font-size:11px;opacity:.85;\">Danger<\/span><\/th>\n<\/tr><\/thead>\n<tbody>\n<tr style=\"background:#f0fdf4;\">\n<td style=\"text-align:left;\"><strong>Class I<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Small machines \u2264 15 kW<br>(pumps, fans, compressors)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 0.71<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">0.71 \u2013 1.8<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">1.8 \u2013 4.5<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 4.5<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align:left;\"><strong>Class II<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Medium machines 15\u201375 kW<br>(without special foundation)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 1.8<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">1.8 \u2013 4.5<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">4.5 \u2013 11.2<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 11.2<\/td>\n<\/tr>\n<tr style=\"background:#f0fdf4;\">\n<td style=\"text-align:left;\"><strong>Class III<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Large machines > 75 kW<br>(rigid foundation)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 2.8<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">2.8 \u2013 7.1<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">7.1 \u2013 18<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 18<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align:left;\"><strong>Class IV<\/strong><br><span style=\"font-size:13px;color:var(--text-muted);\">Large machines > 75 kW<br>(flexible foundation, e.g. steel frame)<\/span><\/td>\n<td class=\"mono\" style=\"background:#dcfce7;font-weight:700;font-size:18px;\">\u2264 4.5<\/td>\n<td class=\"mono\" style=\"background:#ecfccb;font-weight:700;font-size:18px;\">4.5 \u2013 11.2<\/td>\n<td class=\"mono\" style=\"background:#fef3c7;font-weight:700;font-size:18px;\">11.2 \u2013 28<\/td>\n<td class=\"mono\" style=\"background:#fee2e2;font-weight:700;font-size:18px;\">> 28<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n\n<div class=\"info-box\">\n<div class=\"box-title\">\ud83d\udccc How to Use This Table<\/div>\n<p><strong>Step 1:<\/strong> Determine your machine class by power and foundation type.<br>\n<strong>Step 2:<\/strong> Measure overall vibration velocity (mm\/s RMS) on each bearing housing in radial direction.<br>\n<strong>Step 3:<\/strong> Find the zone. <strong>Zone A<\/strong> = newly commissioned or excellent. <strong>Zone B<\/strong> = unrestricted long-term operation. <strong>Zone C<\/strong> = acceptable only for limited periods \u2014 schedule maintenance. <strong>Zone D<\/strong> = damage is occurring \u2014 stop machine as soon as possible.<\/p>\n<p style=\"margin-top:8px;\">Remember: <strong>trends matter more than absolute values.<\/strong> A machine running at 3.0 mm\/s (Zone B for Class II) that was previously at 1.5 mm\/s has doubled \u2014 investigate the cause even though it's still \"acceptable.\" The Balanset-1A's vibrometer mode (F5) displays overall velocity V1s for instant zone assessment.<\/p>\n<\/div>\n\n<div class=\"info-box warning\">\n<div class=\"box-title\">\u26a0\ufe0f ISO 10816 vs. ISO 20816<\/div>\n<p>ISO 10816 was formally superseded by ISO 20816 (published 2016\u20132022). The zone boundaries remain similar for most machine types, but ISO 20816 adds evaluation criteria for displacement and expands machine-specific parts. In practice, ISO 10816 values remain the industry-standard reference. Both the Balanset-1A and most industrial vibration programs still use ISO 10816 zones.<\/p>\n<\/div>\n\n<h2 id=\"monitoring\">From Measurement to Monitoring<\/h2>\n<h3>Trend Analysis<\/h3>\n<p>A single spectrum is a snapshot. The power of vibration analysis is <strong>trend analysis<\/strong> \u2014 tracking changes over time.<\/p>\n<ul>\n<li><strong>Create a baseline:<\/strong> Measure new or known-good equipment. Save spectrums.<\/li>\n<li><strong>Establish intervals:<\/strong> Critical: weekly. Standard: monthly. Auxiliary: quarterly.<\/li>\n<li><strong>Ensure repeatability:<\/strong> Same points, same directions, same operating conditions.<\/li>\n<li><strong>Track changes:<\/strong> A 2\u00d7 increase from baseline is significant even if in ISO Zone A.<\/li>\n<\/ul>\n\n<h3>Decision Algorithm<\/h3>\n<ol>\n<li>Get a quality spectrum (F8 Charts, radial + axial).<\/li>\n<li>Identify the highest peak \u2014 this is the dominant problem.<\/li>\n<li>Match to fault type:\n <ul>\n <li><strong>1\u00d7 dominates \u2192<\/strong> Unbalance \u2192 Balance with Balanset-1A.<\/li>\n <li><strong>2\u00d7 dominates + high axial \u2192<\/strong> Misalignment \u2192 Realign shafts.<\/li>\n <li><strong>Many harmonics \u2192<\/strong> Looseness \u2192 Inspect and tighten.<\/li>\n <li><strong>Non-synchronous peaks \u2192<\/strong> Bearing \u2192 Plan replacement.<\/li>\n <li><strong>GMF + sidebands \u2192<\/strong> Gear \u2192 Check oil, inspect gearbox.<\/li>\n <\/ul>\n<\/li>\n<li>Fix the dominant fault first \u2014 secondary symptoms often disappear.<\/li>\n<\/ol>\n\n<hr style=\"margin:48px 0 24px;border:none;border-top:1px solid var(--border-light);\">\n<p><a href=\"https:\/\/vibromera.eu\/glossary\/\">\u2190 Back to Glossary Index<\/a><\/p>\n<\/article>\n\n<aside class=\"toc-sidebar\">\n<div class=\"toc-box\">\n<h3>On This Page<\/h3>\n<a href=\"#calculators\">Calculators<\/a>\n<a class=\"sub\" href=\"#calculators\">Bearing frequencies<\/a>\n<a class=\"sub\" href=\"#calculators\">ISO 10816 severity<\/a>\n<a class=\"sub\" href=\"#calculators\">RPM\u2194Hz converter<\/a>\n<a class=\"sub\" href=\"#calculators\">Gear Mesh Frequency<\/a>\n<a href=\"#fault-table\">Fault Reference Table<\/a>\n<a href=\"#fft-demo\">Interactive FFT Demo<\/a>\n<a href=\"#fundamentals\">FFT Basics<\/a>\n<a href=\"#units\">Vibration Units<\/a>\n<a href=\"#measurement\">Measurement Technique<\/a>\n<a href=\"#unbalance\">Unbalance (+ spectrums)<\/a>\n<a href=\"#misalignment\">Misalignment (+ spectrums)<\/a>\n<a href=\"#looseness\">Looseness (+ spectrums)<\/a>\n<a href=\"#bearings\">Bearing Defects (+ spectrums)<\/a>\n<a href=\"#gears\">Gear Defects (+ spectrums)<\/a>\n<a href=\"#electrical\">Electrical Faults<\/a>\n<a href=\"#belt\">Belt Drive Problems<\/a>\n<a href=\"#cavitation\">Pump Cavitation<\/a>\n<a href=\"#oilwhirl\">Oil Whirl \/ Oil Whip<\/a>\n<a href=\"#phase\">Phase Analysis<\/a>\n<a href=\"#envelope\">Envelope (Demodulation)<\/a>\n<a href=\"#iso-full\">ISO 10816 Full Table<\/a>\n<a href=\"#monitoring\">Monitoring & Trends<\/a>\n<a href=\"#faq\">FAQ (8 Questions)<\/a>\n<\/div>\n<div class=\"toc-box\" style=\"margin-top:24px;background:var(--navy);border-color:var(--navy);\">\n<h3 style=\"color:#fff;\">Vibration Analyser + Balancer<\/h3>\n<p style=\"color:rgba(255,255,255,.6);font-size:13px;margin-bottom:12px;\">2-channel FFT spectrum analyser, vibrometer, single & two-plane balancing, ISO 1940 tolerance \u2014 all in one portable kit.<\/p>\n<a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\" style=\"display:block;padding:8px 14px;background:var(--blue);color:white;border-radius:6px;text-align:center;font-weight:600;font-size:14px;text-decoration:none;margin-bottom:8px;border-left:none;\">Balanset-1A \u2192<\/a>\n<a href=\"https:\/\/vibromera.eu\/product\/balanset-4\/\" style=\"display:block;padding:8px 14px;background:rgba(255,255,255,.1);color:white;border-radius:6px;text-align:center;font-weight:600;font-size:14px;text-decoration:none;border:1px solid rgba(255,255,255,.2);border-left:none;\">Balanset-4 \u2192<\/a>\n<\/div>\n<\/aside>\n<\/div>\n<\/div>\n<\/main>\n\n\n<section class=\"section-bg alt\" id=\"faq\">\n<div class=\"container\" style=\"max-width:1000px;\">\n<div class=\"section-header\"><h2>Frequently Asked Questions \u2014 Vibration Analysis<\/h2><\/div>\n<div style=\"display:flex;flex-direction:column;gap:16px;\" id=\"faq-list\">\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What is vibration analysis?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">The process of measuring and interpreting mechanical oscillations to diagnose machinery faults without disassembly. FFT decomposes complex vibration into frequency components. Each fault produces a characteristic spectral \"fingerprint\" \u2014 unbalance at 1\u00d7 RPM, misalignment at 2\u00d7, looseness as multiple harmonics, bearing defects at non-synchronous frequencies.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> How do I tell unbalance from misalignment?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\"><strong>Unbalance:<\/strong> dominant 1\u00d7 peak, radial, stable phase, amplitude \u221d speed\u00b2. <strong>Misalignment:<\/strong> significant 2\u00d7 (often \u2265 1\u00d7), high axial vibration, 180\u00b0 phase across coupling.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What are bearing defect frequencies?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Frequencies generated when rolling elements pass over defects. BPFO = outer race, BPFI = inner race, BSF = ball\/roller, FTF = cage. They are NOT integer multiples of shaft speed. Use the bearing frequency calculator above.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What is a good vibration level?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\"><a href=\"https:\/\/vibromera.eu\/glossary\/iso-10816-1\/\">ISO 10816<\/a> zones for Class II (15\u201375 kW): A < 1.8, B < 4.5, C < 11.2, D > 11.2 mm\/s RMS. Trends matter more \u2014 a 2\u00d7 increase from baseline is significant even in Zone A.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> Can Balanset-1A do vibration analysis?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Yes. 2-channel FFT spectrum analyser (F1), vibrometer (F5), detailed charts (F8). Mount both sensors radial+axial on one bearing for instant misalignment detection.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> Time waveform vs. FFT spectrum?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Waveform shows amplitude vs. time \u2014 complex when multiple faults overlap. FFT decomposes into individual frequencies (like a prism splitting light). Each spectrum peak = one vibration source.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> How often should I measure vibration?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Critical: weekly. Standard: monthly. Auxiliary: quarterly. After maintenance: immediately. Consistency is key \u2014 same points, directions, conditions.<\/div><\/details>\n<details style=\"background:var(--white);border:1px solid var(--border-light);border-radius:var(--radius);overflow:hidden;\"><summary style=\"padding:18px 24px;font-weight:700;font-size:16px;cursor:pointer;color:var(--navy);list-style:none;display:flex;align-items:center;gap:10px;\"><span style=\"color:var(--blue);font-size:18px;\">\u25b8<\/span> What causes 0.5\u00d7 (subharmonic) vibration?<\/summary><div style=\"padding:0 24px 18px 52px;font-size:15px;line-height:1.7;color:var(--text);\">Severe mechanical looseness, oil whirl in journal bearings, or cracked shaft. Half-order peaks (0.5\u00d7, 1.5\u00d7) arise from impacts every other revolution. Serious condition \u2014 prompt attention required.<\/div><\/details>\n<\/div>\n<\/div>\n<\/section>\n\n\n<section style=\"padding:32px 0;background:var(--white);border-top:1px solid var(--border-light);\">\n<div class=\"container\" style=\"max-width:1000px;\">\n<h3 style=\"font-family:'DM Serif Display',serif;font-size:22px;color:var(--navy);margin-bottom:20px;\">Related Glossary Articles<\/h3>\n<div style=\"display:grid;grid-template-columns:repeat(3,1fr);gap:16px;\">\n<a href=\"https:\/\/vibromera.eu\/glossary\/balancing\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Rotor Balancing<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">The procedure when spectrum says \"unbalance\"<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/iso-10816-1\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">ISO 10816-1<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">Vibration severity zones and classification<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/unbalance\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Unbalance<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">The most common vibration source<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/iso-1940-1\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">ISO 1940-1<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">G-grade tolerances after balancing<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/natural-frequency\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Natural Frequency<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">Resonance and critical speeds<\/div><\/a>\n<a href=\"https:\/\/vibromera.eu\/glossary\/bearing-fault-frequencies\/\" style=\"display:block;padding:18px;background:var(--beige-light);border:1px solid var(--beige-dark);border-radius:var(--radius-sm);text-decoration:none;box-shadow:var(--shadow-sm);\"><div style=\"font-weight:700;color:var(--navy);font-size:15px;margin-bottom:4px;\">Bearing Fault Frequencies<\/div><div style=\"font-size:13px;color:var(--text-secondary);\">BPFO, BPFI, BSF, FTF in detail<\/div><\/a>\n<\/div>\n<\/div>\n<\/section>\n\n<section class=\"shop-cta\">\n<div class=\"container\">\n<h2>Diagnose First \u2014 Then Balance<\/h2>\n<p>The Balanset-1A is both a 2-channel vibration analyser and a precision field balancer. Identify the fault by spectrum, then fix it \u2014 all with one instrument.<\/p>\n<a href=\"https:\/\/vibromera.eu\/shop\/\" class=\"cta-btn\">Browse Equipment \u2192<\/a>\n<\/div>\n<\/section>\n\n<footer class=\"page-footer\">\n<div class=\"container\"><p><a href=\"https:\/\/vibromera.eu\/glossary\/\">\u2190 Back to Glossary<\/a> | <a href=\"https:\/\/vibromera.eu\/\">vibromera.eu<\/a><\/p><\/div>\n<\/footer>\n\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/chart.js\"><\/script>\n<script>\n\/* ===== BEARING PRESET ===== *\/\nfunction applyBearingPreset(){\n var v=document.getElementById('bc-preset').value;\n if(!v)return;\n var p=v.split(',');\n document.getElementById('bc-balls').value=p[0];\n document.getElementById('bc-bd').value=p[1];\n document.getElementById('bc-pd').value=p[2];\n document.getElementById('bc-angle').value=p[3];\n calcBearing();\n}\n\n\/* ===== BEARING FREQUENCY CALCULATOR ===== *\/\nfunction calcBearing(){\n var rpm=parseFloat(document.getElementById('bc-rpm').value)||0;\n var n=parseFloat(document.getElementById('bc-balls').value)||0;\n var bd=parseFloat(document.getElementById('bc-bd').value)||0;\n var pd=parseFloat(document.getElementById('bc-pd').value)||0;\n var a=(parseFloat(document.getElementById('bc-angle').value)||0)*Math.PI\/180;\n var fs=rpm\/60,r=bd\/pd,ca=Math.cos(a);\n var bpfo=n\/2*(1-r*ca)*fs;\n var bpfi=n\/2*(1+r*ca)*fs;\n var bsf=pd\/(2*bd)*(1-Math.pow(r*ca,2))*fs;\n var ftf=0.5*(1-r*ca)*fs;\n document.getElementById('bc-bpfo').textContent=bpfo.toFixed(2);\n document.getElementById('bc-bpfi').textContent=bpfi.toFixed(2);\n document.getElementById('bc-bsf').textContent=bsf.toFixed(2);\n document.getElementById('bc-ftf').textContent=ftf.toFixed(2);\n document.getElementById('bc-1x').textContent=fs.toFixed(2);\n document.getElementById('bc-ratio').textContent=(bpfo>0&&bpfi>0)?(bpfi\/bpfo).toFixed(3):'\u2014';\n document.getElementById('bc-results').classList.add('active');\n}\n\n\/* ===== ISO 10816 SEVERITY ===== *\/\nvar sevData={\n '1':{limits:[0.71,1.8,4.5],name:'Class I (\u2264 15 kW)'},\n '2':{limits:[1.8,4.5,11.2],name:'Class II (15\u201375 kW)'},\n '3':{limits:[2.8,7.1,18],name:'Class III (large, rigid)'},\n '4':{limits:[4.5,11.2,28],name:'Class IV (large, flexible)'}\n};\nfunction calcSeverity(){\n var vel=parseFloat(document.getElementById('sev-vel').value)||0;\n var cls=document.getElementById('sev-class').value;\n var d=sevData[cls];var zone,zc,label;\n if(vel<=d.limits[0]){zone='A';zc='zone-a';label='Zone A \u2014 Good. Newly commissioned or excellent condition.';}\n else if(vel<=d.limits[1]){zone='B';zc='zone-b';label='Zone B \u2014 Acceptable. Unrestricted long-term operation.';}\n else if(vel<=d.limits[2]){zone='C';zc='zone-c';label='Zone C \u2014 Alert! Plan corrective action.';}\n else{zone='D';zc='zone-d';label='Zone D \u2014 Danger! Immediate action required.';}\n var el=document.getElementById('sev-result');el.style.display='block';el.className='severity-result '+zc;\n el.innerHTML='<strong>'+vel+' mm\/s \u2192 '+zone+'<\/strong> ('+d.name+')<br>'+label+'<br><span style=\"font-size:12px;opacity:.7;\">Limits: A\/B='+d.limits[0]+' | B\/C='+d.limits[1]+' | C\/D='+d.limits[2]+' mm\/s<\/span>';\n}\n\n\/* ===== RPM \u2194 Hz ===== *\/\nfunction convRPM(){var rpm=parseFloat(document.getElementById('conv-rpm').value)||0;var hz=rpm\/60;document.getElementById('conv-hz').value=hz.toFixed(2);updConv(hz);}\nfunction convHz(){var hz=parseFloat(document.getElementById('conv-hz').value)||0;document.getElementById('conv-rpm').value=Math.round(hz*60);updConv(hz);}\nfunction updConv(hz){document.getElementById('conv-1x').textContent=hz.toFixed(2);document.getElementById('conv-2x').textContent=(hz*2).toFixed(2);document.getElementById('conv-3x').textContent=(hz*3).toFixed(2);document.getElementById('conv-period').textContent=hz>0?(1000\/hz).toFixed(2):'\u221e';}\n\n\/* ===== GMF CALCULATOR ===== *\/\nfunction calcGMF(){\n var rpm=parseFloat(document.getElementById('gmf-rpm').value)||0;\n var t1=parseFloat(document.getElementById('gmf-teeth1').value)||0;\n var t2=parseFloat(document.getElementById('gmf-teeth2').value)||0;\n var fs=rpm\/60;var gmf=t1*fs;\n document.getElementById('gmf-val').textContent=gmf.toFixed(1);\n document.getElementById('gmf-2x').textContent=(gmf*2).toFixed(1);\n document.getElementById('gmf-3x').textContent=(gmf*3).toFixed(1);\n document.getElementById('gmf-ratio').textContent=t2>0?(t2\/t1).toFixed(2):'\u2014';\n document.getElementById('gmf-driven').textContent=t2>0?((rpm*t1\/t2).toFixed(1)):'\u2014';\n document.getElementById('gmf-results').classList.add('active');\n}\n\n\/* ===== INTERACTIVE FFT DEMO \u2014 16 FAULT SCENARIOS ===== *\/\n(function(){\n \/* Frequency indices: 1\u00d7=index 2 (at 10Hz steps \u2192 25Hz mapped to ~index2), etc.\n For 50-bin display: bin i \u2192 (i+1)*10 Hz label. 1\u00d7\u224825Hz\u2192i=2, 2\u00d7\u224850Hz\u2192i=4, 3\u00d7\u224875Hz\u2192i=6, etc.\n BPFO\u224889Hz\u2192i=8, BPFI\u2248136Hz\u2192i=13, BSF\u224859Hz\u2192i=5, FTF\u224810Hz\u2192i=0\n GMF=500Hz\u2192i=49(cap at 50) \u2014 use i=48\/49 for GMF range\n Belt freq\u22488Hz\u2192i=0, 2\u00d7belt=16Hz\u2192i=1\n Oil whirl 0.43\u00d7\u224810.7Hz\u2192i=0 *\/\n\n var F={\n \/* === BASELINE === *\/\n normal:{\n d:'Normal \u2014 small 1\u00d7 from residual unbalance. Clean spectrum with low noise floor. All peaks below 1 mm\/s.',\n t:function(x){return .5*Math.sin(x*.2)+(Math.random()-.5)*.15;},\n f:[{i:2,a:.5}]},\n\n \/* === UNBALANCE === *\/\n unbal_static:{\n d:'Static unbalance \u2014 dominant 1\u00d7 peak (25 Hz at 1500 RPM). Pure sinusoid, nearly zero harmonics. Both bearings in-phase. Amplitude \u221d speed\u00b2.',\n t:function(x){return 8.5*Math.sin(x*.2)+(Math.random()-.5)*.3;},\n f:[{i:2,a:8.5},{i:4,a:.3}]},\n\n unbal_dynamic:{\n d:'Dynamic (couple) unbalance \u2014 1\u00d7 dominant like static, but with slight 2\u00d7 from couple component. Bearings ~180\u00b0 out of phase. Two-plane correction needed.',\n t:function(x){return 7*Math.sin(x*.2)+1.5*Math.sin(x*.4+1.2)+(Math.random()-.5)*.4;},\n t2:function(x){return 7*Math.sin(x*.2+Math.PI)+1.5*Math.sin(x*.4+1.2+Math.PI)+(Math.random()-.5)*.4;},\n f:[{i:2,a:7.0},{i:4,a:1.5}]},\n\n \/* === MISALIGNMENT === *\/\n misal_parallel:{\n d:'Parallel misalignment \u2014 2\u00d7 peak \u2265 1\u00d7 in radial direction. 180\u00b0 phase shift across coupling. Waveform is M-shaped (two peaks per revolution).',\n t:function(x){return 4*Math.sin(x*.2)+7*Math.sin(x*.4)+1.2*Math.sin(x*.6)+(Math.random()-.5)*.5;},\n t2:function(x){return 4*Math.sin(x*.2+Math.PI)+7*Math.sin(x*.4+Math.PI)+1.2*Math.sin(x*.6+Math.PI)+(Math.random()-.5)*.5;},\n f:[{i:2,a:4.0},{i:4,a:7.0},{i:6,a:1.2}]},\n\n misal_angular:{\n d:'Angular misalignment \u2014 high 1\u00d7 and 2\u00d7 in axial direction. Axial vibration \u2265 50% of radial. 180\u00b0 axial phase across coupling. Strong 3\u00d7 may appear.',\n t:function(x){return 5*Math.sin(x*.2)+5.5*Math.sin(x*.4)+2.5*Math.sin(x*.6)+(Math.random()-.5)*.5;},\n t2:function(x){return 5*Math.sin(x*.2+Math.PI)+5.5*Math.sin(x*.4+Math.PI)+2.5*Math.sin(x*.6+Math.PI)+(Math.random()-.5)*.5;},\n f:[{i:2,a:5.0},{i:4,a:5.5},{i:6,a:2.5},{i:8,a:.6}]},\n\n \/* === LOOSENESS === *\/\n loose_component:{\n d:'Component looseness \u2014 \"forest\" of harmonics from 1\u00d7 to 10\u00d7+. Sub-harmonic at 0.5\u00d7 indicates impacts every other revolution. Waveform is truncated\/impulsive.',\n t:function(x){var s=0;for(var k=1;k<=8;k++)s+=(4\/k)*Math.sin(x*.2*k+k*.3);s+=1.2*Math.sin(x*.1);return s+(Math.random()-.5)*1.2;},\n f:[{i:0,a:.5},{i:1,a:1.2},{i:2,a:4.0},{i:4,a:3.2},{i:6,a:2.6},{i:8,a:2.1},{i:10,a:1.7},{i:12,a:1.4},{i:14,a:1.1},{i:16,a:.9},{i:18,a:.7},{i:20,a:.5}]},\n\n loose_structural:{\n d:'Structural looseness \u2014 1\u00d7 and 2\u00d7 dominant, few higher harmonics. Strong vertical direction. Phase may be unstable. Often confused with misalignment \u2014 bolt check test differentiates.',\n t:function(x){return 5.5*Math.sin(x*.2)+3.5*Math.sin(x*.4)+.8*Math.sin(x*.6)+(Math.random()-.5)*.6;},\n f:[{i:2,a:5.5},{i:4,a:3.5},{i:6,a:.8}]},\n\n \/* === BEARINGS === *\/\n bear_outer:{\n d:'Outer race defect (BPFO) \u2014 evenly spaced non-synchronous peaks at BPFO harmonics. No 1\u00d7 sidebands (outer ring is stationary). Most common bearing fault (~80% of defects).',\n t:function(x){return .3*Math.sin(x*.2)+1.8*Math.sin(x*2.26)+1.4*Math.sin(x*4.52)+1.0*Math.sin(x*6.78)+.7*Math.sin(x*9.04)+(Math.random()-.5)*1.0;},\n f:[{i:2,a:.3},{i:9,a:2.0},{i:18,a:1.7},{i:27,a:1.4},{i:36,a:1.0},{i:45,a:.7}]},\n\n bear_inner:{\n d:'Inner race defect (BPFI) \u2014 BPFI harmonics with \u00b11\u00d7 sidebands (smaller peaks flanking main peaks). Sidebands arise from load zone modulation as the rotating inner ring carries the defect through the load zone.',\n t:function(x){var imp=Math.sin(x*3.45);var mod=1+.5*Math.sin(x*.2);return .3*Math.sin(x*.2)+imp*mod*1.6+(Math.random()-.5)*.8;},\n f:[{i:2,a:.4},{i:11,a:.5},{i:13,a:1.8},{i:15,a:.5},{i:24,a:.3},{i:26,a:1.3},{i:28,a:.3},{i:39,a:.9}]},\n\n bear_rolling:{\n d:'Rolling element defect (BSF) \u2014 BSF harmonics, 2\u00d7BSF often higher than 1\u00d7BSF (defect strikes both races per revolution). Non-synchronous. Often accompanied by race damage in later stages.',\n t:function(x){return .2*Math.sin(x*.2)+.8*Math.sin(x*1.49)+2.0*Math.sin(x*2.98)+1.1*Math.sin(x*4.47)+(Math.random()-.5)*1.0;},\n f:[{i:2,a:.3},{i:6,a:1.0},{i:12,a:2.2},{i:18,a:1.3},{i:24,a:.7}]},\n\n bear_cage:{\n d:'Cage (train) defect (FTF) \u2014 sub-synchronous peaks at FTF \u2248 0.4\u00d7 shaft speed. Very low frequency. FTF harmonics may appear. Usually accompanies other bearing damage \u2014 rare in isolation.',\n t:function(x){return 2.0*Math.sin(x*.08)+.7*Math.sin(x*.16)+.3*Math.sin(x*.24)+.5*Math.sin(x*.2)+(Math.random()-.5)*.5;},\n f:[{i:0,a:2.2},{i:1,a:.8},{i:2,a:.5},{i:3,a:.3}]},\n\n \/* === GEARS === *\/\n gear_healthy:{\n d:'Healthy gear mesh \u2014 clean GMF peak at teeth \u00d7 shaft speed. No sidebands. Low, single peak indicates normal meshing. GMF amplitude depends on load and gear quality.',\n t:function(x){return .5*Math.sin(x*.2)+2.0*Math.sin(x*6.28)+(Math.random()-.5)*.3;},\n f:[{i:2,a:.5},{i:48,a:2.5}]},\n\n gear_worn:{\n d:'Worn\/damaged gear \u2014 GMF with multiple \u00b11\u00d7 sidebands and 2nd GMF harmonic. Sideband count and amplitude correlate with severity. Dense sidebands = advanced wear or broken tooth.',\n t:function(x){return .8*Math.sin(x*.2)+3.0*Math.sin(x*6.28)*(1+.4*Math.sin(x*.2))+1.5*Math.sin(x*12.56)*(1+.3*Math.sin(x*.2))+(Math.random()-.5)*.6;},\n f:[{i:2,a:.8},{i:46,a:.7},{i:47,a:1.0},{i:48,a:3.5},{i:49,a:1.0},{i:44,a:.4}]},\n\n \/* === OTHER === *\/\n electrical:{\n d:'Electrical fault \u2014 peak at 2\u00d7 line frequency (100 Hz on 50 Hz grid, 120 Hz on 60 Hz). Disappears instantly when power is cut \u2014 mechanical faults decay gradually over seconds.',\n t:function(x){return 1*Math.sin(x*.2)+5.5*Math.sin(x*.628)+(Math.random()-.5)*.3;},\n f:[{i:2,a:1.0},{i:10,a:5.5}]},\n\n belt:{\n d:'Belt drive defect \u2014 sub-synchronous peaks at belt frequency and harmonics (all below 1\u00d7 shaft speed). Belt frequency = \u03c0\u00b7D\u00b7RPM \/ (60\u00b7L). May also show elevated 1\u00d7 from pulley eccentricity.',\n t:function(x){return 2.0*Math.sin(x*.1)+1.5*Math.sin(x*.2)+1.0*Math.sin(x*.3)+.6*Math.sin(x*.4)+(Math.random()-.5)*.4;},\n f:[{i:0,a:2.0},{i:1,a:2.6},{i:2,a:1.0},{i:3,a:.7},{i:4,a:.4}]},\n\n cavitation:{\n d:'Pump cavitation \u2014 broadband high-frequency noise with no discrete peaks. Random bubble collapse creates elevated noise floor above ~200 Hz. Sounds like \"gravel in pump.\" No harmonic structure.',\n t:function(x){return .5*Math.sin(x*.2)+(Math.random()-.5)*4.0;},\n f:(function(){var p=[{i:2,a:.6}];for(var j=15;j<50;j++)p.push({i:j,a:.6+Math.random()*1.8});return p;})()},\n\n oilwhirl:{\n d:'Oil whirl (journal bearings) \u2014 sub-synchronous peak at ~0.43\u00d7 shaft speed (\u2248 10.7 Hz for 1500 RPM). Tracks with speed (proportional). Precursor to destructive oil whip. Only in sleeve\/journal bearings.',\n t:function(x){return 3.5*Math.sin(x*.086)+1.2*Math.sin(x*.2)+(Math.random()-.5)*.5;},\n f:[{i:0,a:3.5},{i:2,a:1.2},{i:4,a:.3}]}\n };\n\n var tc,fc;\n function init(){\n var a=document.getElementById('demo-time'),b=document.getElementById('demo-fft');if(!a||!b)return;\n var tL=[];for(var i=0;i<250;i++)tL.push(i);\n tc=new Chart(a,{type:'line',data:{labels:tL,datasets:[{data:[],borderColor:'#2563eb',backgroundColor:'rgba(37,99,235,.08)',borderWidth:2,pointRadius:0,fill:true},{data:[],borderColor:'#dc2626',backgroundColor:'rgba(220,38,38,.06)',borderWidth:2,pointRadius:0,fill:false,hidden:true}]},options:{responsive:true,maintainAspectRatio:false,animation:{duration:400},plugins:{legend:{display:false},tooltip:{enabled:false}},scales:{x:{grid:{color:'#e2e8f0'},ticks:{display:false},title:{display:true,text:'Time',color:'#94a3b8',font:{size:11}}},y:{grid:{color:'#e2e8f0'},ticks:{color:'#94a3b8',font:{size:10}},title:{display:true,text:'mm\/s',color:'#94a3b8',font:{size:11}}}}}});\n var fL=[];for(var j=1;j<=50;j++)fL.push(j*10);\n fc=new Chart(b,{type:'bar',data:{labels:fL,datasets:[{data:[],backgroundColor:'#2563eb',borderColor:'#1d4ed8',borderWidth:1,barPercentage:1,categoryPercentage:1}]},options:{responsive:true,maintainAspectRatio:false,animation:{duration:400},plugins:{legend:{display:false},tooltip:{callbacks:{title:function(t){return t[0].label+' Hz';},label:function(t){return t.raw.toFixed(2)+' mm\/s';}}}},scales:{x:{grid:{display:false},ticks:{color:'#94a3b8',font:{size:10},maxRotation:0,autoSkip:true,maxTicksLimit:15},title:{display:true,text:'Frequency (Hz)',color:'#94a3b8',font:{size:11}}},y:{beginAtZero:true,grid:{color:'#e2e8f0'},ticks:{color:'#94a3b8',font:{size:10}},title:{display:true,text:'mm\/s',color:'#94a3b8',font:{size:11}}}}}});\n upd('normal');\n document.querySelectorAll('.demo-btn').forEach(function(b){b.addEventListener('click',function(){document.querySelectorAll('.demo-btn').forEach(function(x){x.classList.remove('active');});b.classList.add('active');upd(b.getAttribute('data-fault'));});});\n }\n function upd(type){\n var f=F[type];if(!f)return;\n document.getElementById('demo-desc').textContent=f.d;\n var td=[];for(var i=0;i<250;i++)td.push(f.t(i));\n tc.data.datasets[0].data=td;var all=td.slice();if(f.t2){var td2=[];for(var i=0;i<250;i++)td2.push(f.t2(i));tc.data.datasets[1].data=td2;tc.data.datasets[1].hidden=false;all=all.concat(td2);}else{tc.data.datasets[1].data=[];tc.data.datasets[1].hidden=true;}var mx=Math.max(Math.abs(Math.min.apply(null,all)),Math.max.apply(null,all))*1.2;\n tc.options.scales.y.min=-mx;tc.options.scales.y.max=mx;tc.update();\n var fd=new Array(50).fill(0).map(function(){return Math.random()*.08;});\n var fftData=typeof f.f==='function'?f.f():f.f;\n fftData.forEach(function(p){if(p.i>=0&&p.i<50)fd[p.i]=p.a;});\n fc.data.datasets[0].data=fd;fc.options.scales.y.max=Math.ceil(Math.max.apply(null,fd)*1.3);fc.update();\n }\n if(document.readyState==='loading')document.addEventListener('DOMContentLoaded',init);else init();\n})();\n\n\/* ===== REFERENCE SPECTRUM CHARTS ===== *\/\ndocument.addEventListener('DOMContentLoaded',function(){\n var step=5,size=200,freqRange=1000;\n var labels=[];for(var i=1;i<=size;i++)labels.push(i*step);\n\n function noise(n){var d=[];for(var j=0;j<n;j++)d.push(Math.random()*.15);return d;}\n function mkSpec(peaks){var d=noise(size);peaks.forEach(function(p){if(p.i>=0&&p.i<size)d[p.i]=p.a;});return d;}\n\n function bar(id,peaks,yMax,color,title){\n var el=document.getElementById(id);if(!el)return;\n new Chart(el,{type:'bar',data:{labels:labels,datasets:[{data:mkSpec(peaks),backgroundColor:color||'#2563eb',borderColor:color?color:'#1d4ed8',borderWidth:1,barPercentage:1,categoryPercentage:1}]},options:{responsive:true,maintainAspectRatio:false,animation:{duration:600},plugins:{legend:{display:false},title:{display:!!title,text:title||'',color:'#0a2540',font:{size:13,weight:'bold'}},tooltip:{callbacks:{title:function(t){return t[0].label+' Hz';},label:function(t){return t.raw.toFixed(2)+' mm\/s';}}}},scales:{x:{grid:{display:false},ticks:{color:'#94a3b8',font:{size:9},maxRotation:0,autoSkip:true,maxTicksLimit:20},title:{display:true,text:'Frequency (Hz)',color:'#64748b',font:{size:11}}},y:{beginAtZero:true,max:yMax,grid:{color:'#e2e8f0'},ticks:{color:'#94a3b8',font:{size:10}},title:{display:true,text:'Amplitude (mm\/s)',color:'#64748b',font:{size:11}}}}}});\n }\n\n \/* 1\u00d7 = 25 Hz = index 4 (5Hz step), 2\u00d7 = 50Hz = index 9, 3\u00d7=75Hz=14, etc. *\/\n\n \/* UNBALANCE *\/\n bar('ch-unbal-static',[{i:4,a:8.0}],10,'#2563eb','Static Unbalance');\n bar('ch-unbal-dynamic',[{i:4,a:8.5},{i:9,a:0.5}],10,'#2563eb','Dynamic Unbalance');\n\n \/* MISALIGNMENT *\/\n bar('ch-misal-parallel',[{i:4,a:7.0},{i:9,a:4.5},{i:14,a:2.0}],8,'#d97706','Parallel Misalignment \u2014 Radial');\n bar('ch-misal-angular-r',[{i:4,a:3.0},{i:9,a:7.5},{i:14,a:1.5}],9,'#d97706','Angular Misalignment \u2014 Radial');\n bar('ch-misal-angular-a',[{i:4,a:2.0},{i:9,a:9.0},{i:14,a:2.5}],10,'#e83e8c','Angular Misalignment \u2014 Axial');\n\n \/* LOOSENESS *\/\n var loosePeaks=[{i:1,a:1.0}]; \/* 0.5\u00d7 subharmonic *\/\n for(var k=1;k<=10;k++)loosePeaks.push({i:k*5-1,a:4.0-k*0.32});\n bar('ch-loose-component',loosePeaks,5,'#dc2626','Component Looseness');\n bar('ch-loose-structural',[{i:4,a:5.0},{i:9,a:4.0},{i:14,a:0.8}],6,'#dc2626','Structural Looseness');\n\n \/* BEARINGS \u2014 realistic non-synchronous frequencies *\/\n \/* Assume 6205 @ 1500 RPM: BPFO\u224889Hz(i=17), BPFI\u2248136Hz(i=27), BSF\u224859Hz(i=11), FTF\u224810Hz(i=1) *\/\n bar('ch-bear-outer',[{i:17,a:2.2},{i:35,a:1.9},{i:53,a:1.6},{i:71,a:1.3},{i:89,a:1.0}],3,'#7c3aed','Outer Race (BPFO) \u2014 6205 @ 1500 RPM');\n\n \/* BPFI with \u00b11\u00d7 sidebands (1\u00d7=25Hz=5 bins) *\/\n var bpfiPeaks=[];\n for(var h=1;h<=5;h++){\n var bi=27*h-1;var amp=2.5-h*0.35;\n if(bi<size){bpfiPeaks.push({i:bi,a:amp});if(bi-5>=0)bpfiPeaks.push({i:bi-5,a:amp*0.35});if(bi+5<size)bpfiPeaks.push({i:bi+5,a:amp*0.35});}\n }\n bar('ch-bear-inner',bpfiPeaks,3,'#7c3aed','Inner Race (BPFI) with \u00b11\u00d7 Sidebands');\n\n bar('ch-bear-rolling',[{i:11,a:1.0},{i:23,a:2.5},{i:35,a:1.2},{i:47,a:0.8}],3,'#7c3aed','Rolling Element (BSF) \u2014 2\u00d7BSF Dominant');\n bar('ch-bear-cage',[{i:1,a:1.8},{i:3,a:0.9},{i:5,a:0.5}],2.5,'#7c3aed','Cage (FTF) \u2014 Sub-synchronous');\n\n \/* GEARS \u2014 GMF = 20teeth \u00d7 25Hz = 500Hz = index 99 *\/\n bar('ch-gear-eccentric',[{i:4,a:1.5},{i:94,a:1.2},{i:99,a:3.5},{i:104,a:1.2}],4.5,'#0a2540','Gear Eccentricity \u2014 GMF \u00b1 1\u00d7');\n bar('ch-gear-wear',[{i:94,a:0.8},{i:99,a:3.5},{i:104,a:0.8},{i:193,a:2.0},{i:188,a:0.6},{i:198,a:0.6}],4.5,'#0a2540','Gear Wear \u2014 GMF + 2\u00d7GMF with Sidebands');\n\n \/* ENVELOPE \u2014 demodulated bearing spectrum, clean BPFI harmonics *\/\n var envPeaks=[];\n for(var e=1;e<=8;e++){var ei=27*e-1;if(ei<size)envPeaks.push({i:ei,a:2.8-e*0.28});}\n bar('ch-envelope',envPeaks,3.5,'#059669','Envelope Spectrum \u2014 BPFI Harmonics (Demodulated)');\n\n \/* BELT DRIVE \u2014 sub-synchronous belt freq + harmonics *\/\n \/* Belt freq ~8 Hz = index 1, 2\u00d7belt=16Hz=index 2, 3\u00d7belt=24Hz=index 3 (below 1\u00d7 at index 4) *\/\n bar('ch-belt',[{i:0,a:1.8},{i:1,a:2.5},{i:2,a:1.6},{i:3,a:1.0},{i:4,a:0.6},{i:5,a:0.4}],3.5,'#0891b2','Belt Drive \u2014 Belt Frequency Harmonics (sub-synchronous)');\n\n \/* CAVITATION \u2014 broadband high-frequency hump *\/\n var cavPeaks=[];\n for(var c=40;c<180;c++){cavPeaks.push({i:c,a:0.5+Math.random()*1.2});}\n cavPeaks.push({i:4,a:0.8}); \/* small 1\u00d7 from shaft *\/\n bar('ch-cavitation',cavPeaks,2.5,'#0d9488','Pump Cavitation \u2014 Broadband High-Frequency Noise');\n\n \/* OIL WHIRL \u2014 peak at ~0.43\u00d7 = ~10.7Hz \u2248 index 1 (5Hz step) *\/\n bar('ch-oilwhirl',[{i:1,a:3.2},{i:3,a:0.6},{i:4,a:1.5},{i:9,a:0.4}],4,'#a855f7','Oil Whirl \u2014 Sub-synchronous at ~0.43\u00d7 Shaft Speed');\n\n \/* Auto-calc on load *\/\n calcBearing();calcSeverity();convRPM();\n});\n<\/script>\n<\/body>\n<\/html><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Vibration Analysis \u2014 Beginner’s Guide to Spectrum Diagnostics \u2014 Vibromera Home \u2192 Glossary \u2192 Vibration Analysis Vibration Analysis \u2014 Spectrum Diagnostics Guide \ud83d\udccc Canonical Reference Article \u2014 vibromera.eu From FFT fundamentals to fault diagnosis: learn to read vibration spectrums, calculate bearing defect frequencies, assess severity per ISO 10816, and diagnose […]<\/p>\n","protected":false},"author":2,"featured_media":3441,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ai_generated_summary":"","footnotes":""},"categories":[5],"tags":[],"class_list":["post-6156","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-solutions"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/posts\/6156","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/comments?post=6156"}],"version-history":[{"count":10,"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/posts\/6156\/revisions"}],"predecessor-version":[{"id":21238,"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/posts\/6156\/revisions\/21238"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/media\/3441"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/media?parent=6156"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/categories?post=6156"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/pt_br\/wp-json\/wp\/v2\/tags?post=6156"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}