Dynamic Shaft Balancing Instruction \u2013 ISO 21940 | Vibromera<\/title>\n<meta name=\"description\" content=\"Dynamic shaft balancing instruction: 7-step two-plane procedure, trial weight formula, ISO 21940 G-grades, correction angles. Field data: 12.4 \u2192 0.8 mm\/s.\">\n<meta name=\"keywords\" content=\"dynamic shaft balancing instruction, dynamic balancing, static balancing, rotor balancing, field balancing, two-plane balancing, single-plane balancing, trial weight calculation, correction weight, vibration analyzer, ISO 1940, ISO 21940, balance quality grade, fan balancing, shaft balancing, Balanset-1A\">\n<meta name=\"author\" content=\"Nikolai Shelkovenko\">\n<meta name=\"robots\" content=\"index, follow, max-image-preview:large, max-snippet:-1\">\n\n\n\n\n\n\n\n\n\n\n\n\n<meta name=\"geo.region\" content=\"EE\">\n<meta name=\"geo.placename\" content=\"Tallinn\">\n<meta name=\"geo.position\" content=\"59.437;24.7536\">\n<meta name=\"ICBM\" content=\"59.437, 24.7536\">\n\n\n<meta property=\"og:type\" content=\"article\">\n<meta property=\"og:url\" content=\"https:\/\/vibromera.eu\/example\/dynamic-shaft-balancing-instruction\/\">\n<meta property=\"og:title\" content=\"Dynamic Shaft Balancing Instruction: Field Procedure, ISO 21940 Grades\">\n<meta property=\"og:description\" content=\"Dynamic shaft balancing instruction. 7-step field procedure, trial weight formula, ISO grades, correction planes. Real data: 12.4 \u2192 0.8 mm\/s.\">\n<meta property=\"og:image\" content=\"https:\/\/vibromera.eu\/wp-content\/uploads\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.jpg\">\n<meta property=\"og:image:width\" content=\"1024\">\n<meta property=\"og:image:height\" content=\"683\">\n<meta property=\"og:image:alt\" content=\"Balanset-1A portable balancer and vibration analyzer \u2014 complete kit\">\n<meta property=\"og:site_name\" content=\"Vibromera\">\n<meta property=\"og:locale\" content=\"en_US\">\n<meta property=\"og:locale:alternate\" content=\"de_DE\">\n<meta property=\"og:locale:alternate\" content=\"es_ES\">\n<meta property=\"og:locale:alternate\" content=\"fr_FR\">\n<meta property=\"og:locale:alternate\" content=\"pt_PT\">\n<meta property=\"og:locale:alternate\" content=\"ru_RU\">\n<meta property=\"article:published_time\" content=\"2024-03-15T00:00:00+00:00\">\n<meta property=\"article:modified_time\" content=\"2026-02-11T00:00:00+00:00\">\n<meta property=\"article:author\" content=\"https:\/\/vibromera.eu\/author\/nikolai\/\">\n<meta property=\"article:section\" content=\"Knowledge Base\">\n<meta property=\"article:tag\" content=\"dynamic balancing\">\n<meta property=\"article:tag\" content=\"shaft balancing\">\n<meta property=\"article:tag\" content=\"ISO 21940\">\n<meta property=\"article:tag\" content=\"field balancing\">\n<meta property=\"article:tag\" content=\"Balanset-1A\">\n\n\n<meta name=\"twitter:card\" content=\"summary_large_image\">\n<meta name=\"twitter:title\" content=\"Dynamic Shaft Balancing Instruction | Field Guide with ISO 21940\">\n<meta name=\"twitter:description\" content=\"Static vs dynamic balance, 7-step procedure, trial weight calculation, G-grade table. Field data included.\">\n<meta name=\"twitter:image\" content=\"https:\/\/vibromera.eu\/wp-content\/uploads\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.jpg\">\n<meta name=\"twitter:image:alt\" content=\"Balanset-1A portable balancer and vibration analyzer \u2014 complete kit\">\n\n\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"TechArticle\",\n \"headline\": \"Dynamic Shaft Balancing Instruction: Static vs Dynamic Balance, Field Procedure & ISO 21940 Grades\",\n \"description\": \"Dynamic shaft balancing instruction for field engineers. Covers static vs dynamic balance physics, types of unbalance, 7-step two-plane balancing procedure, trial weight calculation, angle measurement, ISO 21940-11 balance quality grades, and correction plane placement.\",\n \"author\": {\n \"@type\": \"Person\",\n \"name\": \"Nikolai Shelkovenko\",\n \"jobTitle\": \"CEO & Field Engineer\",\n \"worksFor\": {\n \"@type\": \"Organization\",\n \"name\": \"Vibromera\",\n \"url\": \"https:\/\/vibromera.eu\"\n }\n },\n \"publisher\": {\n \"@type\": \"Organization\",\n \"name\": \"Vibromera\",\n \"url\": \"https:\/\/vibromera.eu\",\n \"logo\": {\n \"@type\": \"ImageObject\",\n \"url\": \"https:\/\/vibromera.eu\/wp-content\/uploads\/vibromera-logo.png\"\n }\n },\n \"datePublished\": \"2024-03-15\",\n \"dateModified\": \"2026-02-11\",\n \"mainEntityOfPage\": \"https:\/\/vibromera.eu\/example\/dynamic-shaft-balancing-instruction\/\",\n \"about\": [\n { \"@type\": \"Thing\", \"name\": \"Dynamic balancing\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q1227750\" },\n { \"@type\": \"Thing\", \"name\": \"Rotor (electric)\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q193881\" },\n { \"@type\": \"Thing\", \"name\": \"Vibration\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q3695508\" },\n { \"@type\": \"Thing\", \"name\": \"ISO 1940\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q28134046\" }\n ],\n \"speakable\": {\n \"@type\": \"SpeakableSpecification\",\n \"cssSelector\": [\".db-hero__subtitle\", \".db-definition__text\"]\n },\n \"proficiencyLevel\": \"Expert\",\n \"dependencies\": \"Vibration sensor (accelerometer), laser tachometer or reflective marker, portable balancing instrument\"\n}\n<\/script>\n\n\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"HowTo\",\n \"name\": \"How to Perform Two-Plane Dynamic Balancing in the Field\",\n \"description\": \"Step-by-step procedure for field balancing a rotor using a portable vibration analyzer with two-plane capability.\",\n \"totalTime\": \"PT45M\",\n \"tool\": [\n { \"@type\": \"HowToTool\", \"name\": \"Portable balancing instrument (e.g. Balanset-1A)\" },\n { \"@type\": \"HowToTool\", \"name\": \"Two vibration sensors (accelerometers)\" },\n { \"@type\": \"HowToTool\", \"name\": \"Laser tachometer or reflective tape + optical sensor\" },\n { \"@type\": \"HowToTool\", \"name\": \"Set of trial weights (bolts, washers, hose clamps)\" },\n { \"@type\": \"HowToTool\", \"name\": \"Angle-measuring tool or protractor\" },\n { \"@type\": \"HowToTool\", \"name\": \"Welding equipment or hose clamps for weight attachment\" }\n ],\n \"step\": [\n {\n \"@type\": \"HowToStep\",\n \"position\": 1,\n \"name\": \"Prepare the rotor and mount sensors\",\n \"text\": \"Clean bearing housings. Mount vibration sensor 1 near Plane 1 (drive end) and sensor 2 near Plane 2 (non-drive end). Attach reflective tape to the shaft for the tachometer. Connect all sensors to the balancing instrument.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 2,\n \"name\": \"Measure initial vibration\",\n \"text\": \"Start the rotor and let it reach stable operating speed. Record vibration amplitude and phase at both sensors. This is the baseline measurement.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 3,\n \"name\": \"Install trial weight in Plane 1\",\n \"text\": \"Stop the rotor. Attach a trial weight of known mass at an arbitrary angular position in Plane 1. Mark the position. Restart the rotor and record vibration at both sensors.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 4,\n \"name\": \"Move trial weight to Plane 2\",\n \"text\": \"Stop the rotor. Remove the trial weight from Plane 1 and attach it at an arbitrary angular position in Plane 2. Restart the rotor and record vibration at both sensors.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 5,\n \"name\": \"Calculate correction weights\",\n \"text\": \"The instrument uses the three measurements (baseline + two trial runs) to compute influence coefficients and determine the mass and angle of correction weights needed in both planes.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 6,\n \"name\": \"Install correction weights\",\n \"text\": \"Attach the calculated correction weights at the specified angles in Plane 1 and Plane 2. Measure angles from the trial weight position in the direction of rotation.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 7,\n \"name\": \"Verify balance\",\n \"text\": \"Start the rotor and measure final vibration. Confirm that residual vibration is below the acceptable threshold per ISO 21940-11. If not, perform a trim run.\"\n }\n ]\n}\n<\/script>\n\n\n<script type=\"application\/ld+json\">{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"Product\",\n \"name\": \"Balanset-1A\",\n \"description\": \"Portable 2-channel dynamic balancing instrument and vibration analyzer for field balancing of rotors in one or two planes.\",\n \"brand\": {\n \"@type\": \"Brand\",\n \"name\": \"Vibromera\"\n },\n \"manufacturer\": {\n \"@type\": \"Organization\",\n \"name\": \"Vibromera\",\n \"url\": \"https:\/\/vibromera.eu\"\n },\n \"url\": \"https:\/\/vibromera.eu\/product\/balanset-1\/\",\n \"offers\": {\n \"@type\": \"Offer\",\n \"price\": \"1975.00\",\n \"priceCurrency\": \"EUR\",\n \"priceValidUntil\": \"2026-12-31\",\n \"availability\": \"https:\/\/schema.org\/InStock\",\n \"url\": \"https:\/\/vibromera.eu\/product\/balanset-1\/\"\n },\n \"additionalProperty\": [\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Number of channels\",\n \"value\": \"2\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Balancing planes\",\n \"value\": \"1 or 2\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Vibration measurement range\",\n \"value\": \"0.5\u201380 mm\/s RMS\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Frequency range\",\n \"value\": \"5\u2013550 Hz\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"RPM range\",\n \"value\": \"300\u2013100,000\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Phase measurement accuracy\",\n \"value\": \"\u00b11\u00b0\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Sensor type\",\n \"value\": \"Piezoelectric accelerometer\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Software\",\n \"value\": \"Balanset-1A (Windows)\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Weight\",\n \"value\": \"3.5 kg (complete kit)\"\n }\n ]\n}<\/script>\n\n\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"FAQPage\",\n \"mainEntity\": [\n {\n \"@type\": \"Question\",\n \"name\": \"What is the difference between static and dynamic balancing?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Static balancing corrects unbalance in a single plane \u2014 the rotor's centre of gravity is shifted back to the rotation axis. It works for narrow, disc-shaped parts (diameter-to-width ratio greater than 7:1). Dynamic balancing corrects unbalance in two planes simultaneously, addressing both force and couple unbalance. It is required for any elongated rotor where masses are distributed along the shaft length.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"How do I calculate trial weight mass for field balancing?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Use the formula: Mt = Mr \u00d7 K \/ (Rt \u00d7 (N\/100)\u00b2), where Mr is rotor mass (g), K is support stiffness coefficient (1 = soft, 3 = average, 5 = rigid), Rt is trial weight installation radius (cm), and N is RPM. The trial weight should produce at least 20\u201330% amplitude change or 20\u201330\u00b0 phase shift. Use our online trial weight calculator at vibromera.eu\/trial-weight-mass-calculator\/ for instant results. At low RPM (below 500), use the 10% static rule: trial mass = 10% of rotor mass \/ correction radius.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"When should I use single-plane vs two-plane balancing?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Use single-plane (static) balancing for narrow disc-shaped rotors where the diameter is more than 7 times the width \u2014 flywheels, grinding wheels, saw blades. Use two-plane (dynamic) balancing for elongated rotors \u2014 shafts, fans with wide impellers, mulcher rotors, rolls. If in doubt, two-plane balancing is always the safer choice.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"What ISO standard covers rotor balancing tolerances?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"ISO 21940-11:2016 is the current standard for rigid rotor balancing. It replaced the older ISO 1940-1:2003. It defines balance quality grades (G0.4 to G4000) that specify the maximum permissible residual specific unbalance based on rotor type and operating speed. Common grades include G6.3 for fans and pumps, G2.5 for electric motors, and G1.0 for turbocharger rotors.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"How do I measure the angle for correction weight placement?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"The balancing instrument calculates the correction angle relative to the trial weight position. Mark where you placed the trial weight (this is your 0\u00b0 reference). Then measure the indicated angle in the direction of rotor rotation from that reference point. The correction weight goes at the resulting position. If the instrument says to remove weight, place it 180\u00b0 opposite.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"Can I balance a rotor without removing it from the machine?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Yes \u2014 this is called field balancing or in-situ balancing. You mount vibration sensors on the bearing housings, attach a tachometer reference, and run the machine at operating speed. A portable instrument like the Balanset-1A guides you through the trial weight sequence and calculates corrections. 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}\n}\n<\/style>\n<\/head>\n\n<body>\n<div class=\"db-article\">\n\n\n<nav class=\"db-breadcrumb\" aria-label=\"Breadcrumb\">\n <a href=\"https:\/\/vibromera.eu\/\">Home<\/a>\n <span>\u203a<\/span>\n <a href=\"https:\/\/vibromera.eu\/knowledge-base\/\">Knowledge Base<\/a>\n <span>\u203a<\/span>\n Dynamic Shaft Balancing Instruction\n<\/nav>\n\n\n<header class=\"db-hero\">\n <div class=\"db-hero__inner\">\n <div class=\"db-hero__badge\">Field Balancing \u00b7 Complete Guide<\/div>\n <h1 class=\"db-hero__title\">Dynamic Shaft Balancing Instruction: <em>Static vs Dynamic<\/em>, Field Procedure & ISO 21940 Grades<\/h1>\n <p class=\"db-hero__subtitle\">Everything a field engineer needs to balance rotors on-site \u2014 from the physics of unbalance to the final verification run. Seven-step procedure, trial weight formulas, correction angle measurement, and ISO tolerance tables. Tested on 2,000+ rotors across fans, mulchers, crushers, and shafts.<\/p>\n <div class=\"db-hero__meta\">\n <span class=\"db-hero__meta-item\">\u270e Nikolai Shelkovenko<\/span>\n <span class=\"db-hero__meta-item\">Updated: Feb 2026<\/span>\n <span class=\"db-hero__meta-item\">~18 min read<\/span>\n <\/div>\n <\/div>\n<\/header>\n\n\n<div class=\"db-layout\">\n\n\n<aside class=\"db-toc\" aria-label=\"Table of Contents\">\n <div class=\"db-toc__title\">Contents<\/div>\n <ol class=\"db-toc__list\">\n <li class=\"db-toc__item\"><a href=\"#what-is\" class=\"db-toc__link\">What Is Dynamic Balancing<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#static-vs-dynamic\" class=\"db-toc__link\">Static vs Dynamic Balance<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#types-of-unbalance\" class=\"db-toc__link\">Four Types of Unbalance<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#single-vs-two\" class=\"db-toc__link\">Single-Plane vs Two-Plane<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#iso-grades\" class=\"db-toc__link\">ISO 21940-11 Balance Grades<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#field-procedure\" class=\"db-toc__link\">7-Step Field Procedure<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#trial-weight\" class=\"db-toc__link\">Trial Weight Calculation<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#angle-measurement\" class=\"db-toc__link\">Correction Angle Measurement<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#correction-planes\" class=\"db-toc__link\">Correction Planes & Sensors<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#applications\" class=\"db-toc__link\">Applications by Machine Type<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#weight-methods\" class=\"db-toc__link\">Weight Attachment Methods<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#common-mistakes\" class=\"db-toc__link\">Common Mistakes<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#field-report\" class=\"db-toc__link\">Field Report: Mulcher Rotor<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#fan-balancing\" class=\"db-toc__link\">Fan Balancing Walkthrough<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#faq\" class=\"db-toc__link\">FAQ<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#equipment\" class=\"db-toc__link\">Equipment<\/a><\/li>\n <\/ol>\n<\/aside>\n\n\n<main class=\"db-content\">\n\n\n<h2 id=\"what-is\">What Is Dynamic Balancing?<\/h2>\n\n<div class=\"db-definition\">\n <div class=\"db-definition__label\">Definition<\/div>\n <p class=\"db-definition__text\"><strong>Dynamic balancing<\/strong> is the process of measuring and correcting the uneven mass distribution of a rotating body (rotor) while it spins at operating speed. Unlike static balancing, which corrects mass offset in a single plane, dynamic balancing addresses imbalance in <strong>two or more planes simultaneously<\/strong>, eliminating both centrifugal force and rocking couple that cause bearing vibration.<\/p>\n<\/div>\n\n<p>Every rotating part \u2014 from a 200 kg mulcher rotor to a 5 g dental drill spindle \u2014 has some residual unbalance. Manufacturing tolerances, material inconsistencies, corrosion, and accumulated deposits shift the mass centre away from the geometric rotation axis. The result is a centrifugal force that grows with the square of speed: double the RPM and the force quadruples.<\/p>\n\n<p>A rotor spinning at 3,000 RPM with just 10 g of unbalance at a 150 mm radius generates roughly 150 N of rotating force \u2014 enough to destroy bearings in weeks. Dynamic balancing reduces this force to a level specified by international standards (ISO 21940‑11, formerly ISO 1940), extending bearing life from months to years and cutting vibration\u2011related downtime.<\/p>\n\n<div class=\"db-note\">\n <div class=\"db-note__title\">Field engineer's note<\/div>\n <div class=\"db-note__text\">In 13 years of field work, unbalance has been the root cause in roughly 40% of the vibration complaints I investigate. It is also the easiest fault to fix on\u2011site \u2014 a trained technician with the right instrument finishes in 30\u201345 minutes without removing the rotor.<\/div>\n<\/div>\n\n\n<h2 id=\"static-vs-dynamic\">Static vs Dynamic Balance<\/h2>\n\n<div class=\"db-compare\">\n <div class=\"db-compare__card db-compare__card--static\">\n <div class=\"db-compare__badge\">Single plane<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-compare__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/\u0420\u043e\u0442\u0435\u0440_statika-1024x549.jpg\" alt=\"Rotor in static imbalance \u2014 heavy point rotates to the bottom\" width=\"750\" height=\"402\">\n <div class=\"db-compare__title\">Static Balance<\/div>\n <div class=\"db-compare__text\">\n <p>The rotor's centre of gravity is offset from the rotation axis in <strong>one plane<\/strong>. When placed on knife\u2011edge supports, the heavy side rolls to the bottom \u2014 you can detect this without spinning.<\/p>\n <p><strong>Correction:<\/strong> add or remove mass at a single angular position opposite the heavy spot. One correction plane is enough.<\/p>\n <p><strong>Applies to:<\/strong> narrow disc\u2011shaped parts where diameter > 7\u00d7 width \u2014 flywheels, grinding wheels, single\u2011disc impellers, saw blades, brake discs.<\/p>\n <\/div>\n <\/div>\n\n <div class=\"db-compare__card db-compare__card--dynamic\">\n <div class=\"db-compare__badge\">Two planes<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-compare__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/long-rotor-1024x549.jpg\" alt=\"Long rotor in dynamic imbalance \u2014 two mass offsets in different planes\" width=\"750\" height=\"402\">\n <div class=\"db-compare__title\">Dynamic Balance<\/div>\n <div class=\"db-compare__text\">\n <p>Two (or more) mass offsets sit in <strong>different planes<\/strong> along the rotor length. They may cancel each other statically \u2014 the rotor sits still on knife\u2011edges \u2014 but create a <strong>rocking couple<\/strong> when spinning. This couple cannot be detected or corrected without rotation.<\/p>\n <p><strong>Correction:<\/strong> two compensating weights in two separate planes. The instrument calculates mass and angle for each plane from the influence coefficient matrix.<\/p>\n <p><strong>Applies to:<\/strong> elongated rotors \u2014 shafts, fans with wide impellers, mulcher rotors, rollers, multi\u2011stage pump impellers, turbines.<\/p>\n <\/div>\n <\/div>\n<\/div>\n\n<div class=\"db-warning\">\n <strong>Key distinction:<\/strong> a statically balanced rotor can still have severe dynamic imbalance. The forces in one plane exactly oppose those in another, so the rotor does not roll on supports \u2014 but the moment it spins, the couple creates violent vibration at the bearings. Two\u2011plane dynamic balancing catches what static methods miss.\n<\/div>\n\n\n<h2 id=\"types-of-unbalance\">Four Types of Unbalance<\/h2>\n\n<p>ISO 21940‑11 distinguishes four fundamental unbalance patterns. Understanding which one dominates helps choose the correct balancing strategy.<\/p>\n\n<div class=\"db-unbalance-grid\">\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"16\" y=\"24\" width=\"32\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"8\" y1=\"32\" x2=\"16\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"48\" y1=\"32\" x2=\"56\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"40\" cy=\"36\" r=\"4\" fill=\"#d4622b\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Static<\/div>\n <div class=\"db-unbalance-card__text\">Single heavy spot. CG displaced parallel to rotation axis. Detectable at rest. Single\u2011plane correction.<\/div>\n <\/div>\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"12\" y=\"24\" width=\"40\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"4\" y1=\"32\" x2=\"12\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"52\" y1=\"32\" x2=\"60\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"20\" cy=\"22\" r=\"3.5\" fill=\"#d4622b\"\/>\n <circle cx=\"44\" cy=\"42\" r=\"3.5\" fill=\"#d4622b\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Couple<\/div>\n <div class=\"db-unbalance-card__text\">Two equal masses 180\u00b0 apart in different planes. Net force = 0, but creates a torque (couple). Invisible at rest.<\/div>\n <\/div>\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"12\" y=\"24\" width=\"40\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"4\" y1=\"32\" x2=\"12\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"52\" y1=\"32\" x2=\"60\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"32\" cy=\"36\" r=\"3\" fill=\"#c49a1a\"\/>\n <circle cx=\"20\" cy=\"22\" r=\"3\" fill=\"#d4622b\"\/>\n <circle cx=\"44\" cy=\"42\" r=\"3\" fill=\"#d4622b\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Quasi\u2011static<\/div>\n <div class=\"db-unbalance-card__text\">Combination of static + couple where principal inertia axis intersects rotation axis at a point other than the CG.<\/div>\n <\/div>\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"12\" y=\"24\" width=\"40\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"4\" y1=\"32\" x2=\"12\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"52\" y1=\"32\" x2=\"60\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"22\" cy=\"22\" r=\"3\" fill=\"#d4622b\"\/>\n <circle cx=\"34\" cy=\"38\" r=\"4\" fill=\"#d4622b\"\/>\n <circle cx=\"46\" cy=\"26\" r=\"2.5\" fill=\"#c49a1a\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Dynamic<\/div>\n <div class=\"db-unbalance-card__text\">General case: principal inertia axis neither intersects nor parallels rotation axis. The most common real\u2011world pattern. Two\u2011plane correction mandatory.<\/div>\n <\/div>\n<\/div>\n\n<p>In practice, almost every rotor you encounter in the field has dynamic unbalance \u2014 a combination of force and couple components. That is why two\u2011plane balancing is the default procedure for any rotor that is not a thin disc.<\/p>\n\n\n\n<h2 id=\"single-vs-two\">When to Use Single\u2011Plane vs Two\u2011Plane Balancing<\/h2>\n\n<p>The deciding factor is the rotor's <strong>geometry ratio L\/D<\/strong> (axial length to outer diameter) combined with its operating speed.<\/p>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Criterion<\/th>\n <th>Single\u2011Plane (1 sensor)<\/th>\n <th>Two\u2011Plane (2 sensors)<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td><strong>L\/D ratio<\/strong><\/td>\n <td>L\/D < 0.14 (diameter > 7\u00d7 width)<\/td>\n <td>L\/D \u2265 0.14<\/td>\n <\/tr>\n <tr>\n <td><strong>Typical parts<\/strong><\/td>\n <td>Grinding wheel, flywheel, single\u2011disc impeller, pulley, brake disc, saw blade<\/td>\n <td>Fan rotor, mulcher, shaft, roller, multi\u2011stage pump, turbine, crusher<\/td>\n <\/tr>\n <tr>\n <td><strong>Unbalance types corrected<\/strong><\/td>\n <td>Static only (force)<\/td>\n <td>Static + couple + dynamic (force + moment)<\/td>\n <\/tr>\n <tr>\n <td><strong>Correction planes<\/strong><\/td>\n <td>1<\/td>\n <td>2<\/td>\n <\/tr>\n <tr>\n <td><strong>Measurement runs<\/strong><\/td>\n <td>2 (initial + 1 trial)<\/td>\n <td>3 (initial + 2 trials, one per plane)<\/td>\n <\/tr>\n <tr>\n <td><strong>Time on site<\/strong><\/td>\n <td>15\u201320 min<\/td>\n <td>30\u201345 min<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<div class=\"db-note\">\n <div class=\"db-note__title\">Rule of thumb<\/div>\n <div class=\"db-note__text\">If the correction planes are separated by less than \u2153 of the rotor's bearing span, cross\u2011coupling between planes is small and single\u2011plane balancing may work even for L\/D > 0.14. But if you have a two\u2011channel instrument, always use two planes \u2014 it takes only 10 extra minutes and catches couple unbalance that single\u2011plane misses.<\/div>\n<\/div>\n\n\n\n<h2 id=\"iso-grades\">ISO 21940\u201111 Balance Quality Grades<\/h2>\n\n<p>ISO 21940\u201111 (the successor to ISO 1940\u20111) assigns each class of rotating machinery a <strong>balance quality grade G<\/strong>, defined as the maximum permissible velocity of the rotor's centre of gravity in mm\/s. The permissible residual specific unbalance <em>e<sub>per<\/sub><\/em> (in g\u00b7mm\/kg) is derived from the grade and the operating speed:<\/p>\n\n<div class=\"db-formula\">\n <div class=\"db-formula__label\">Permissible specific unbalance<\/div>\n <div class=\"db-formula__expression\">e<sub>per<\/sub> = G \u00d7 1000 \/ \u03c9 = G \u00d7 1000 \/ (2\u03c0 \u00d7 RPM \/ 60)<\/div>\n <div class=\"db-formula__legend\">\n <strong>e<sub>per<\/sub><\/strong> \u2014 permissible residual specific unbalance, g\u00b7mm\/kg<br>\n <strong>G<\/strong> \u2014 balance quality grade (e.g. 6.3 means 6.3 mm\/s)<br>\n <strong>\u03c9<\/strong> \u2014 angular velocity, rad\/s<br>\n <strong>RPM<\/strong> \u2014 operating speed, rev\/min\n <\/div>\n<\/div>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Grade<\/th>\n <th>e\u00b7\u03c9, mm\/s<\/th>\n <th>Machine types<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td><code>G 0.4<\/code><\/td>\n <td>0.4<\/td>\n <td>Gyroscopes, spindles of precision grinding machines<\/td>\n <\/tr>\n <tr>\n <td><code>G 1.0<\/code><\/td>\n <td>1.0<\/td>\n <td>Turbochargers, gas turbines, small electric armatures with special requirements<\/td>\n <\/tr>\n <tr>\n <td><code>G 2.5<\/code><\/td>\n <td>2.5<\/td>\n <td>Electric motors, generators, medium\/large turbines, pumps with special requirements<\/td>\n <\/tr>\n <tr>\n <td><code>G 6.3<\/code><\/td>\n <td>6.3<\/td>\n <td>Fans, pumps, process machinery, flywheels, centrifuges, general industrial machinery<\/td>\n <\/tr>\n <tr>\n <td><code>G 16<\/code><\/td>\n <td>16<\/td>\n <td>Agricultural machinery, crushers, drive shafts (cardan), parts of crushing machines<\/td>\n <\/tr>\n <tr>\n <td><code>G 40<\/code><\/td>\n <td>40<\/td>\n <td>Passenger car wheels, crankshaft assemblies (series production)<\/td>\n <\/tr>\n <tr>\n <td><code>G 100<\/code><\/td>\n <td>100<\/td>\n <td>Crankshaft assemblies of large slow marine diesel engines<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<h3>Worked Example: Fan Rotor<\/h3>\n<p>A centrifugal fan rotor weighs 80 kg, operates at 1,450 RPM, and the correction radius is 250 mm. Required grade: G 6.3.<\/p>\n\n<div class=\"db-formula\">\n <div class=\"db-formula__label\">Calculation<\/div>\n <div class=\"db-formula__expression\">e<sub>per<\/sub> = 6.3 \u00d7 1000 \/ (2\u03c0 \u00d7 1450 \/ 60) = 6300 \/ 151.8 \u2248 41.5 g\u00b7mm\/kg<\/div>\n <div class=\"db-formula__legend\">\n Total permissible unbalance = 41.5 \u00d7 80 = <strong>3,320 g\u00b7mm<\/strong><br>\n At correction radius 250 mm: max residual mass = 3320 \/ 250 = <strong>13.3 g<\/strong> per plane<br>\n That means each correction plane may retain no more than 13.3 g of unbalance \u2014 roughly the weight of three M6 washers.\n <\/div>\n<\/div>\n\n<p>Related standards: <a href=\"https:\/\/vibromera.eu\/glossary\/iso-21940-11\/\">ISO 21940\u201111<\/a> (rigid rotors), <a href=\"https:\/\/vibromera.eu\/glossary\/iso-21940-12\/\">ISO 21940\u201112<\/a> (flexible rotors), <a href=\"https:\/\/vibromera.eu\/glossary\/iso-10816-3-vibration-severity\/\">ISO 10816‑3<\/a> (vibration severity limits), <a href=\"https:\/\/vibromera.eu\/glossary\/iso-1940\/\">ISO 1940<\/a> (legacy predecessor).<\/p>\n\n\n\n<h2 id=\"field-procedure\">Seven\u2011Step Field Balancing Procedure<\/h2>\n\n<p>This is the influence coefficient method for two\u2011plane field balancing, applied with a portable instrument such as the <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\">Balanset\u20111A<\/a>. The same logic works with any two\u2011channel balancing analyser.<\/p>\n\n<div class=\"db-steps\">\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">1<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Prepare the Rotor & Mount Sensors<\/div>\n <div class=\"db-step__text\">\n Clean bearing housings from dirt and grease \u2014 sensors must sit flush on the metal surface. Mount vibration sensor 1 on the bearing housing closest to <strong>Plane 1<\/strong> (usually the drive end). Mount sensor 2 near <strong>Plane 2<\/strong> (non\u2011drive end). Attach reflective tape to the shaft for the laser tachometer. Connect all cables to the measuring unit.\n <\/div>\n\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">2<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Measure Initial Vibration (Run 0)<\/div>\n <div class=\"db-step__text\">\n Start the rotor and bring it to stable operating speed. The instrument measures vibration amplitude (mm\/s) and phase angle (\u00b0) at both sensors simultaneously. This is the <strong>baseline<\/strong> \u2014 the \"sickness\" of the rotor before treatment. Record the values and stop the machine.\n <\/div>\n <div class=\"db-step__tip\">Field tip: Wait at least 10\u201315 seconds after the RPM stabilises before recording. Thermal transients and air currents settle out in the first few seconds.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697405_121.jpg\" alt=\"Initial vibration measurement on a rotor \u2014 Balanset-1A screen showing baseline readings\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">3<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Install Trial Weight in Plane 1 (Run 1)<\/div>\n <div class=\"db-step__text\">\n Stop the rotor. Attach a <strong>trial weight<\/strong> of known mass at an arbitrary angular position in Plane 1. Mark this position clearly \u2014 it becomes your 0\u00b0 reference for angle measurement later. Restart the rotor and record vibration at both sensors. The instrument now knows how the rotor's vibration field changes when mass is added in Plane 1.\n <\/div>\n <div class=\"db-step__tip\">Field tip: Use a bolt with a washer clamped to the rotor rim, or a hose clamp with a nut for quick attachment. The trial weight should produce a measurable vibration change (\u226530 % amplitude change or \u226530\u00b0 phase shift at either sensor).<\/div>\n <div class=\"db-note\" style=\"margin-top:12px;\">\n <div class=\"db-note__icon\">\u2696<\/div>\n <div class=\"db-note__text\"><strong>How much should the trial weight weigh?<\/strong> Use the empirical formula: <code style=\"background:rgba(0,0,0,0.06); padding:2px 6px; border-radius:3px; font-family:'JetBrains Mono',monospace; font-size:13px;\">M<sub>t<\/sub> = M<sub>r<\/sub> \u00d7 K \/ (R<sub>t<\/sub> \u00d7 (N\/100)\u00b2)<\/code> where M<sub>r<\/sub> = rotor mass (g), K = support stiffness coefficient (1\u20135, use 3 for average), R<sub>t<\/sub> = installation radius (cm), N = RPM. Or use our <a href=\"https:\/\/vibromera.eu\/trial-weight-mass-calculator\/\" style=\"color:var(--db-forest); font-weight:600;\">online trial weight calculator<\/a> \u2014 enter your rotor parameters and get the recommended mass instantly.<\/div>\n <\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697404_121.jpg\" alt=\"Installing a calibration weight on the first correction plane\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">4<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Move Trial Weight to Plane 2 (Run 2)<\/div>\n <div class=\"db-step__text\">\n Stop the rotor. Remove the trial weight from Plane 1. Attach the same trial weight (or one of similar known mass) at an arbitrary position in Plane 2. Mark this second reference point. Restart and record vibration at both sensors. Now the instrument has the complete influence coefficient matrix \u2014 four complex coefficients linking unbalance in either plane to vibration at either sensor.\n <\/div>\n <div class=\"db-step__tip\">Field tip: If you use a different trial weight mass in Plane 2, enter the correct value in the software \u2014 the maths adjusts automatically.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697403_121.jpg\" alt=\"Moving the trial weight to the second correction plane for the second trial run\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">5<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Calculate Correction Weights<\/div>\n <div class=\"db-step__text\">\n The instrument solves the influence coefficient equations and displays: <strong>mass (g)<\/strong> and <strong>angle (\u00b0)<\/strong> for Plane 1, and mass (g) and angle (\u00b0) for Plane 2. The angle is measured from the trial weight position in the direction of rotor rotation. If the software indicates \"remove,\" it means the correction weight should go 180\u00b0 opposite the indicated \"add\" position.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">6<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Install Correction Weights<\/div>\n <div class=\"db-step__text\">\n Remove the trial weight from Plane 2. Fabricate or select correction weights matching the calculated masses. Measure the angle from the trial weight reference mark in the direction of rotation. Attach the correction weights firmly \u2014 welding, hose clamps, set\u2011screw weights, or bolts depending on the machine type and speed.\n <\/div>\n <div class=\"db-step__tip\">Field tip: If you cannot place a weight at the exact angle (e.g. only bolt holes available), use the weight\u2011splitting function \u2014 the instrument decomposes the correction vector into two components at the nearest available positions.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10421367.png\" alt=\"Diagram showing correction weight angle measurement \u2014 from trial weight position in direction of rotation\" width=\"447\" height=\"358\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">7<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Verify Balance (Check Run)<\/div>\n <div class=\"db-step__text\">\n Restart the rotor and record the final vibration. Compare against the initial baseline and against the ISO 21940‑11 tolerance for your machine class. If vibration is within specification, you are done. If not, the instrument can perform a <strong>trim run<\/strong> \u2014 it uses the existing influence coefficients to calculate a small additional correction without new trial weights.\n <\/div>\n <div class=\"db-step__tip\">Field tip: One trim run is usually enough. If you need more than two trims, something has changed between runs \u2014 check for loose weights, thermal growth, or speed variation.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697402_121-1024x549.jpg\" alt=\"Final verification run showing significantly reduced vibration levels after balancing\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n<\/div>\n\n\n<div class=\"db-cta\">\n <div class=\"db-cta__title\">All Seven Steps \u2014 One Instrument<\/div>\n <div class=\"db-cta__text\">The Balanset\u20111A walks you through the entire two\u2011plane procedure on screen. Two accelerometers, laser tachometer, Windows software, and carrying case included.<\/div>\n <div class=\"db-cta__price\">\u20ac1,975<\/div>\n <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\" class=\"db-cta__btn\">View Balanset\u20111A<\/a>\n <a href=\"https:\/\/wa.me\/351927292960\" class=\"db-cta__btn db-cta__btn--whatsapp\" target=\"_blank\" rel=\"noopener\">WhatsApp<\/a>\n<\/div>\n\n\n\n<h2 id=\"trial-weight\">Trial Weight Calculation<\/h2>\n\n<p>The trial weight must be heavy enough to produce a noticeable vibration change, but light enough not to overload bearings or create a dangerous condition. The standard empirical formula accounts for rotor mass, correction radius, operating speed, and support stiffness:<\/p>\n\n<div class=\"db-formula\">\n <div class=\"db-formula__label\">Trial weight mass formula<\/div>\n <div class=\"db-formula__expression\">M<sub>t<\/sub> = M<sub>r<\/sub> \u00d7 K \/ (R<sub>t<\/sub> \u00d7 (N \/ 100)\u00b2)<\/div>\n <div class=\"db-formula__legend\">\n <strong>M<sub>t<\/sub><\/strong> \u2014 trial weight mass, grams<br>\n <strong>M<sub>r<\/sub><\/strong> \u2014 rotor mass, grams<br>\n <strong>K<\/strong> \u2014 support stiffness coefficient (1 = soft mounts, 3 = average, 5 = rigid foundation)<br>\n <strong>R<sub>t<\/sub><\/strong> \u2014 trial weight installation radius, cm<br>\n <strong>N<\/strong> \u2014 operating speed, RPM\n <\/div>\n<\/div>\n\n<p style=\"margin-top:12px;\">Don't want to do the maths by hand? Use our <a href=\"https:\/\/vibromera.eu\/trial-weight-mass-calculator\/\" style=\"color:var(--db-forest); font-weight:600;\">online trial weight calculator \u2197<\/a> \u2014 enter your rotor parameters, support type, and vibration level, and get the recommended mass instantly.<\/p>\n\n<h3>Worked Examples (K = 3, average stiffness)<\/h3>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Machine<\/th>\n <th>Rotor mass<\/th>\n <th>RPM<\/th>\n <th>Radius<\/th>\n <th>Trial weight (K = 3)<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td>Mulcher rotor<\/td>\n <td>120 kg<\/td>\n <td>2,200<\/td>\n <td>30 cm<\/td>\n <td>360,000 \/ (30 \u00d7 484) \u2248 <strong>25 g<\/strong><\/td>\n <\/tr>\n <tr>\n <td>Industrial fan<\/td>\n <td>80 kg<\/td>\n <td>1,450<\/td>\n <td>40 cm<\/td>\n <td>240,000 \/ (40 \u00d7 210.25) \u2248 <strong>29 g<\/strong><\/td>\n <\/tr>\n <tr>\n <td>Centrifuge drum<\/td>\n <td>45 kg<\/td>\n <td>3,000<\/td>\n <td>15 cm<\/td>\n <td>135,000 \/ (15 \u00d7 900) = <strong>10 g<\/strong><\/td>\n <\/tr>\n <tr>\n <td>Crusher shaft<\/td>\n <td>250 kg<\/td>\n <td>900<\/td>\n <td>25 cm<\/td>\n <td>750,000 \/ (25 \u00d7 81) \u2248 <strong>370 g<\/strong><\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<div class=\"db-note\">\n <div class=\"db-note__title\">Practical tip: verify the response<\/div>\n <div class=\"db-note__text\">The formula gives the minimum trial mass that should produce a measurable response. After the trial run, check that the phase shifted by at least 20\u201330\u00b0 and the amplitude changed by 20\u201330%. If the response is too small, double or triple the trial mass and repeat. At very low RPM (< 500), the formula may yield impractically large values \u2014 in that case, use 10% of rotor weight divided by the correction radius as a starting point.<\/div>\n<\/div>\n\n\n\n<h2 id=\"angle-measurement\">Correction Angle Measurement<\/h2>\n\n<p>The balancing instrument outputs two numbers per plane: <strong>mass<\/strong> (how much weight) and <strong>angle<\/strong> (where to place it). The angle is always referenced to the trial weight position.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center; max-width:680px;\">\n <img decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10448629.png\" alt=\"Balanset-1A software \u2014 two-plane balancing result window showing correction weight mass and angle on polar diagram\" width=\"680\" style=\"display:block; margin:0 auto; border-radius:6px; box-shadow:0 2px 12px rgba(0,0,0,0.12);\">\n <figcaption style=\"font-size:13px; color:#666; margin-top:8px;\">Balanset\u20111A result screen: the software calculates correction mass and angle for each plane and displays vectors on a polar chart. Red vectors show the required correction; green shows residual vibration after trim run.<\/figcaption>\n<\/figure>\n\n<h3>How to Measure the Angle<\/h3>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10431396.png\" alt=\"Polar graph showing correction weight angle relative to trial weight position\" width=\"275\" height=\"469\" style=\"display:block; margin:24px auto;\">\n\n<ul class=\"db-inline-list\">\n <li><strong>Reference point (0\u00b0):<\/strong> the angular position where you placed the trial weight. Mark it clearly on the rotor before the trial run.<\/li>\n <li><strong>Measurement direction:<\/strong> always in the direction of rotor rotation.<\/li>\n <li><strong>Reading the angle:<\/strong> the instrument displays angle f\u2081 for Plane 1 and f\u2082 for Plane 2. From the trial weight mark, count that many degrees in the rotation direction \u2014 that is where the correction weight goes.<\/li>\n <li><strong>If removing mass:<\/strong> place the correction at 180\u00b0 opposite the indicated \"add\" position.<\/li>\n<\/ul>\n\n<h3>Weight Splitting to Fixed Positions<\/h3>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10431665.png\" alt=\"Polar graph showing weight split into two fixed bolt-hole positions\" width=\"308\" height=\"514\" style=\"display:block; margin:24px auto;\">\n\n<p>When the rotor has pre\u2011drilled holes or fixed mounting positions (e.g. fan blade bolts), you may not be able to place a weight at the exact calculated angle. The Balanset\u20111A includes a <strong>weight splitting function<\/strong>: you enter the angles of the two nearest available positions, and the software decomposes the single correction vector into two smaller weights at those positions. The combined effect matches the original vector.<\/p>\n\n\n\n<h2 id=\"correction-planes\">Correction Planes & Sensor Placement<\/h2>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10485475.png\" alt=\"Diagram showing correction planes and sensor measurement points on a rotor\" width=\"513\" height=\"294\" style=\"display:block; margin:16px auto;\">\n\n<p>The correction plane is the axial position on the rotor where you add or remove mass. The sensor measures vibration at the nearest bearing. A few key rules:<\/p>\n\n<ul class=\"db-inline-list\">\n <li><strong>Sensor goes on the bearing housing<\/strong> \u2014 as close to the bearing centreline as possible, in the radial direction (horizontal preferred).<\/li>\n <li><strong>Plane 1 corresponds to Sensor 1,<\/strong> Plane 2 to Sensor 2. Keep the numbering consistent or the software will swap correction planes.<\/li>\n <li><strong>Maximise plane separation:<\/strong> the further apart the two correction planes, the better the couple resolution. Minimum practical separation is \u2153 of the bearing span.<\/li>\n <li><strong>Choose accessible positions:<\/strong> the correction plane must be a location where you can physically attach weights \u2014 a flange edge, bolt circle, rim, or welding surface.<\/li>\n<\/ul>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/\u0421\u043d\u0438\u043c\u043e\u043a-\u044d\u043a\u0440\u0430\u043d\u0430-\u043e\u0442-2024-05-14-01-28-32-1024x573.png\" alt=\"Mulcher rotor showing correction planes (blue 1 and 2) and weight installation points (red 1 and 2)\" width=\"750\" height=\"420\" style=\"display:block; margin:24px auto;\">\n\n<p>In the photo above, a mulcher rotor is prepared for two\u2011plane balancing. Blue markers 1 and 2 indicate the sensor positions on bearing housings. Red markers 1 and 2 show the correction planes \u2014 in this case, the flanged ends of the rotor body where weights will be welded.<\/p>\n\n<h3>Cantilever (Overhung) Rotor<\/h3>\n\n<p>Cantilever rotors \u2014 fan impellers, flywheels mounted outboard of the bearing span, pump impellers \u2014 require a different sensor and plane layout. Both correction planes are on the same side of the bearings, and sensor placement must account for the overhung mass amplifying couple unbalance.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/2plschcons-1.png\" alt=\"Schematic diagram of sensor connection and correction plane layout for a cantilever (overhung) rotor \u2014 Balanset-1A two-plane setup\" width=\"750\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Sensor connection diagram for a cantilever rotor: both correction planes are outboard of the bearing span.<\/figcaption>\n<\/figure>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/%D0%A1%D0%BD%D0%B8%D0%BC%D0%BE%D0%BA-%D1%8D%D0%BA%D1%80%D0%B0%D0%BD%D0%B0-%D0%BE%D1%82-2024-05-14-01-29-01-1024x659.png\" alt=\"Cantilever rotor balancing in the field \u2014 sensor and correction plane positions marked on actual equipment\" width=\"750\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Field example: cantilever rotor with sensor and correction plane positions marked.<\/figcaption>\n<\/figure>\n\n\n\n<h2 id=\"applications\">Applications by Machine Type<\/h2>\n\n<div class=\"db-app-cards\">\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Industrial Fans & Blowers<\/div>\n <div class=\"db-app-card__specs\">600\u20133,600 RPM \u00b7 G 6.3 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Most common field balancing task. Centrifugal fans, axial fans, blowers. Watch for dust buildup on blades \u2014 it shifts balance over time. Re\u2011balance after cleaning or blade replacement.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Mulcher & Flail Mower Rotors<\/div>\n <div class=\"db-app-card__specs\">1,800\u20132,500 RPM \u00b7 G 16 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Heavy rotors (80\u2013200 kg) with replaceable flails. Unbalance appears after flail wear or replacement. Correct in two planes at the rotor end\u2011flanges. Typical improvement: 12 \u2192 1 mm\/s.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Crushers & Hammer Mills<\/div>\n <div class=\"db-app-card__specs\">600\u20131,200 RPM \u00b7 G 16 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Extremely heavy rotors (200\u20131,000+ kg). Trial weights are large (5\u201315 kg bolts). Low RPM means large permissible unbalance \u2014 but impact loads and bearing cost still justify balancing.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Centrifuges<\/div>\n <div class=\"db-app-card__specs\">1,000\u201310,000 RPM \u00b7 G 2.5\u20136.3 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Basket or disc centrifuges in food, chemical, and pharma. High speed demands tight tolerance. Field balancing avoids lengthy disassembly. Check for product buildup inside drum.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Electric Motors & Generators<\/div>\n <div class=\"db-app-card__specs\">750\u20133,600 RPM \u00b7 G 2.5 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Motor armatures are factory balanced, but re\u2011balancing is needed after winding repair, bearing replacement, or coupling changes. Test with coupling half attached for best results.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Combine Harvester Augers & Rotors<\/div>\n <div class=\"db-app-card__specs\">400\u20131,200 RPM \u00b7 G 16 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Long augers and threshing rotors pick up soil and crop residue imbalance. Seasonal balancing before harvest prevents bearing failure in the field. Correction weights welded to flights.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Pump Impellers<\/div>\n <div class=\"db-app-card__specs\">1,450\u20133,600 RPM \u00b7 G 6.3 \u00b7 Single or Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Overhung impellers often need only single\u2011plane correction if narrow. For multi\u2011stage pumps, each impeller is balanced individually on a mandrel before assembly.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Turbochargers<\/div>\n <div class=\"db-app-card__specs\">30,000\u2013300,000 RPM \u00b7 G 1.0 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Ultra\u2011high speed demands G 1.0 or tighter tolerance. Material removal by grinding \u2014 no welded weights at these speeds. Requires high\u2011frequency vibration sensors.<\/div>\n <\/div>\n\n<\/div>\n\n\n\n<h2 id=\"weight-methods\">Weight Attachment Methods<\/h2>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Method<\/th>\n <th>Attachment<\/th>\n <th>Best for<\/th>\n <th>Limits<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td><strong>Welding<\/strong><\/td>\n <td>Steel washers or plates tack\u2011welded to rotor rim<\/td>\n <td>Mulchers, crushers, heavy industrial rotors<\/td>\n <td>Permanent. Cannot use on aluminium or stainless without special rod<\/td>\n <\/tr>\n <tr>\n <td><strong>Bolts & nuts<\/strong><\/td>\n <td>Bolts through pre\u2011drilled holes with locknuts<\/td>\n <td>Fan impellers, flywheels, coupling flanges<\/td>\n <td>Requires existing holes or new drilling<\/td>\n <\/tr>\n <tr>\n <td><strong>Hose clamps<\/strong><\/td>\n <td>Stainless\u2011steel hose clamp with weight sandwiched<\/td>\n <td>Shafts, rollers, cylindrical rotors in the field<\/td>\n <td>Temporary or semi\u2011permanent. Verify clamp torque<\/td>\n <\/tr>\n <tr>\n <td><strong>Set\u2011screw clip\u2011on<\/strong><\/td>\n <td>Pre\u2011made clip\u2011on weights (like tyre weights)<\/td>\n <td>Fan blades, thin rims, light rotors<\/td>\n <td>Limited mass range. May slip at high RPM<\/td>\n <\/tr>\n <tr>\n <td><strong>Adhesive (epoxy)<\/strong><\/td>\n <td>Weight glued to surface<\/td>\n <td>Precision rotors, clean environments<\/td>\n <td>Requires clean dry surface. Temperature limit ~120\u00b0C<\/td>\n <\/tr>\n <tr>\n <td><strong>Material removal<\/strong><\/td>\n <td>Drilling or grinding material away from heavy side<\/td>\n <td>Turbochargers, high\u2011speed spindles, impellers<\/td>\n <td>Permanent and precise but irreversible. Use when adding weight is not safe<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n\n\n<h2 id=\"common-mistakes\">Common Mistakes in Field Balancing<\/h2>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>#<\/th>\n <th>Mistake<\/th>\n <th>Consequence<\/th>\n <th>Fix<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td>1<\/td>\n <td><strong>Sensor mounted on a guard or cover<\/strong><\/td>\n <td>Resonance of the cover distorts amplitude and phase readings \u2192 wrong correction<\/td>\n <td>Always mount on the bearing housing metal surface<\/td>\n <\/tr>\n <tr>\n <td>2<\/td>\n <td><strong>Trial weight too light<\/strong><\/td>\n <td>Phase and amplitude change is within noise \u2192 influence coefficients are unreliable<\/td>\n <td>Ensure \u226530% amplitude change or \u226530\u00b0 phase shift at at least one sensor<\/td>\n <\/tr>\n <tr>\n <td>3<\/td>\n <td><strong>Speed variation between runs<\/strong><\/td>\n <td>Vibration at 1\u00d7 changes with RPM\u00b2 \u2014 even 5% speed change corrupts the data<\/td>\n <td>Use a tachometer for precise RPM tracking. Wait for speed to stabilise<\/td>\n <\/tr>\n <tr>\n <td>4<\/td>\n <td><strong>Forgetting to remove the trial weight<\/strong><\/td>\n <td>Correction calculation includes trial weight effect \u2192 result is meaningless<\/td>\n <td>Follow a strict routine: remove trial weight before installing correction weights<\/td>\n <\/tr>\n <tr>\n <td>5<\/td>\n <td><strong>Mixing up Plane 1 and Plane 2<\/strong><\/td>\n <td>Correction weights go in the wrong planes \u2192 vibration increases<\/td>\n <td>Label sensors and planes clearly. Sensor 1 \u2192 Plane 1, Sensor 2 \u2192 Plane 2<\/td>\n <\/tr>\n <tr>\n <td>6<\/td>\n <td><strong>Measuring angle opposite to rotation<\/strong><\/td>\n <td>Correction goes 360\u00b0 \u2212 f instead of f \u2192 opposite side of rotor<\/td>\n <td>Confirm rotation direction before starting. Always measure in rotation direction<\/td>\n <\/tr>\n <tr>\n <td>7<\/td>\n <td><strong>Thermal growth during runs<\/strong><\/td>\n <td>Bearing clearance changes between cold start runs \u2192 drifting measurements<\/td>\n <td>Either warm up to steady state before run 0, or complete all runs quickly (<5 min apart)<\/td>\n <\/tr>\n <tr>\n <td>8<\/td>\n <td><strong>Using single\u2011plane on a long rotor<\/strong><\/td>\n <td>Couple unbalance remains uncorrected \u2192 vibration may even increase at the far bearing<\/td>\n <td>Use two\u2011plane balancing for any rotor where L\/D \u2265 0.14 or plane separation is significant<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n\n\n<h2 id=\"field-report\">Field Report: Mulcher Rotor Balancing<\/h2>\n\n<div class=\"db-field-report\">\n <div class=\"db-field-report__badge\">Real field data \u00b7 February 2025<\/div>\n <div class=\"db-field-report__title\">Flail Mulcher \u2014 Maschio Bisonte 280<\/div>\n\n <div class=\"db-field-report__grid\">\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Vibration before<\/div>\n <div class=\"db-field-report__value db-field-report__value--before\">12.4 mm\/s<\/div>\n <\/div>\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Vibration after<\/div>\n <div class=\"db-field-report__value db-field-report__value--after\">0.8 mm\/s<\/div>\n <\/div>\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Reduction<\/div>\n <div class=\"db-field-report__value\" style=\"color:#fff;\">93.5%<\/div>\n <\/div>\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Time on site<\/div>\n <div class=\"db-field-report__value\" style=\"color:#fff;\">38 min<\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-field-report__detail\">\n <p><strong>Machine:<\/strong> Maschio Bisonte 280 flail mulcher, 165 kg rotor, 2,100 RPM PTO speed. Client reported severe vibration after replacing 8 flails.<\/p>\n <p><strong>Setup:<\/strong> Two accelerometers on bearing housings, laser tachometer on PTO shaft. Balanset-1A two-plane mode.<\/p>\n <p><strong>Run 0:<\/strong> Sensor 1 = 12.4 mm\/s @ 47\u00b0, Sensor 2 = 8.9 mm\/s @ 213\u00b0. ISO 10816-3 zone D (danger).<\/p>\n <p><strong>Trial runs:<\/strong> 500 g trial weight used in both planes. Clear response \u2014 amplitude change >60% at both sensors.<\/p>\n <p><strong>Correction:<\/strong> Plane 1: 340 g welded at 128\u00b0. Plane 2: 215 g welded at 276\u00b0.<\/p>\n <p><strong>Verification:<\/strong> Sensor 1 = 0.8 mm\/s, Sensor 2 = 0.6 mm\/s. ISO zone A (good). No trim run needed.<\/p>\n <\/div>\n<\/div>\n\n\n\n<h2 id=\"fan-balancing\">Two\u2011Plane Dynamic Balancing of a Fan<\/h2>\n\n<p>Industrial fans \u2014 centrifugal, axial, and mixed\u2011flow \u2014 are among the most common rotors balanced in the field. The procedure below walks through a real two\u2011plane job on a radial fan using the Balanset\u20111A.<\/p>\n\n<h3>Determining Planes and Installing Sensors<\/h3>\n\n<p>Clean the surfaces for sensor installation from dirt and oil. Sensors must fit snugly to the metal surface of the bearing housing \u2014 never mount on covers, guards, or unsupported sheet\u2011metal panels.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/2plschcons-1.png\" alt=\"Sensor connection diagram for fan two-plane balancing \u2014 Balanset-1A setup with correction planes marked\" width=\"536\" height=\"283\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Sensor connection and correction plane layout for a cantilever\u2011mounted fan impeller.<\/figcaption>\n<\/figure>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/%D0%A1%D0%BD%D0%B8%D0%BC%D0%BE%D0%BA-%D1%8D%D0%BA%D1%80%D0%B0%D0%BD%D0%B0-%D0%BE%D1%82-2024-05-14-01-29-01-1024x659.png\" alt=\"Fan rotor with sensor positions and correction planes marked in red and green zones\" width=\"750\" height=\"483\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Sensor and correction plane positions on a fan rotor: Sensor 1 (red) near front, Sensor 2 (green) near rear.<\/figcaption>\n<\/figure>\n\n<ul class=\"db-inline-list\">\n <li><strong>Sensor 1 (red):<\/strong> Install closer to the front of the fan (Plane 1 side).<\/li>\n <li><strong>Sensor 2 (green):<\/strong> Install closer to the rear of the fan (Plane 2 side).<\/li>\n <li><strong>Plane 1 (red zone):<\/strong> Correction plane on the impeller disc, closer to the front.<\/li>\n <li><strong>Plane 2 (green zone):<\/strong> Correction plane closer to the back plate or hub.<\/li>\n<\/ul>\n\n<p>Connect both vibration sensors and the laser tachometer to the Balanset\u20111A. Attach reflective tape to the shaft or hub for RPM reference.<\/p>\n\n<h3>Balancing Process<\/h3>\n\n<p>Start the fan and take initial vibration measurements (Run 0). Install a trial weight of known mass on Plane 1 at an arbitrary point, run the fan, and record the vibration change (Run 1). Move the trial weight to Plane 2 at an arbitrary point, run the fan again, and record (Run 2). The Balanset\u20111A software uses all three measurements to calculate the correction mass and angle for each plane.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/5384253216985827502_120.jpg\" alt=\"Installing correction weights on a fan impeller after two-plane balancing with Balanset-1A\" width=\"622\" height=\"395\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Correction weights installed on the fan impeller at positions calculated by the Balanset\u20111A.<\/figcaption>\n<\/figure>\n\n<h3>Angle Measurement for Fan Correction Weights<\/h3>\n\n<p>The angle is measured from the trial weight position in the direction of fan rotation \u2014 exactly as described in the <a href=\"#angle-measurement\">Correction Angle Measurement<\/a> section above. Mark where the trial weight was placed (0\u00b0 reference), then count the indicated angle along the rotation direction to find the correction weight position.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/IMG_20190305_162103-1024x589.jpg\" alt=\"Balanset-1A software screen showing two-plane balancing results for a fan \u2014 polar diagram with correction vectors\" width=\"750\" height=\"431\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Balanset\u20111A two\u2011plane balancing result screen: correction mass and angle displayed for both planes.<\/figcaption>\n<\/figure>\n\n<p>Based on the angles and masses calculated by the software, install the correction weights on Plane 1 and Plane 2. Run the fan once more and verify that vibration has dropped to an acceptable level per <a href=\"#iso-grades\">ISO 21940\u201111<\/a> (typically G 6.3 for general\u2011purpose fans). If residual vibration is still above target, perform one trim run.<\/p>\n\n\n\n<h2 id=\"faq\">Frequently Asked Questions<\/h2>\n\n<div class=\"db-faq\">\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n What is the difference between static and dynamic balancing?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Static balancing corrects unbalance in a single plane \u2014 the rotor's centre of gravity is shifted back to the rotation axis. It works for narrow, disc-shaped parts where diameter is greater than 7 times the width. Dynamic balancing corrects unbalance in two planes simultaneously, addressing both force and couple unbalance. It is required for any elongated rotor where masses are distributed along the shaft length. A rotor can be statically balanced yet dynamically unbalanced \u2014 the couple component is invisible until the rotor spins.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n How do I calculate the trial weight mass for field balancing?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Use the formula: M<sub>t<\/sub> = M<sub>r<\/sub> \u00d7 K \/ (R<sub>t<\/sub> \u00d7 (N\/100)\u00b2), where M is in grams, R in cm, and N in RPM. K is the support stiffness coefficient (1 = soft, 3 = average, 5 = rigid). The goal is to produce at least 20\u201330% amplitude change or 20\u201330\u00b0 phase shift. Or skip the maths and use our <a href=\"https:\/\/vibromera.eu\/trial-weight-mass-calculator\/\" style=\"color:var(--db-forest); font-weight:600;\">online trial weight calculator<\/a>. At low speeds below 500 RPM, use the 10% static rule instead: trial mass = 10% of rotor mass \/ correction radius.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n When should I use single-plane vs two-plane balancing?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Use single-plane for narrow disc-shaped rotors where diameter exceeds 7 times the axial width \u2014 flywheels, grinding wheels, saw blades. Use two-plane for anything longer: shafts, fan impellers, mulcher rotors, rollers, multi-stage pump assemblies. When in doubt, always choose two-plane \u2014 it catches couple unbalance that single-plane misses, and only adds one extra measurement run (about 10 minutes).\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n What ISO standard covers rotor balancing tolerances?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n ISO 21940-11:2016 is the current standard for rigid rotors. It replaced ISO 1940-1:2003. It defines balance quality grades from G 0.4 (gyroscopes) to G 4000 (slow marine diesel crankshafts). Common grades: G 6.3 for fans and pumps, G 2.5 for electric motors, G 1.0 for turbocharger rotors, G 16 for agricultural machinery and crushers. The grade times the angular velocity gives the maximum permissible CG velocity in mm\/s \u2014 from there you calculate the allowable residual mass at the correction radius.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n How do I measure the angle for correction weight placement?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n The instrument calculates the correction angle relative to the trial weight position. Mark where you placed the trial weight \u2014 this is your 0\u00b0 reference. Then measure the indicated angle in the direction of rotor rotation from that reference point. The correction weight goes at the resulting position. If the instrument says to remove weight, place it 180\u00b0 opposite. Use a protractor or divide the circumference into marked segments before starting.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n Can I balance a rotor without removing it from the machine?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Yes \u2014 this is called field balancing or in-situ balancing. You mount vibration sensors on the bearing housings, attach a tachometer reference, and run the machine at operating speed. A portable instrument like the Balanset-1A guides you through the trial weight sequence and calculates corrections. Field balancing saves hours of disassembly time, eliminates alignment errors from reinstallation, and balances the rotor under real operating conditions \u2014 including the effect of coupling, thermal growth, and actual bearing stiffness.\n <\/div>\n <\/div>\n <\/div>\n\n<\/div>\n\n\n\n<h2 id=\"equipment\">Equipment for Field Balancing<\/h2>\n\n<p>The <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\">Balanset\u20111A<\/a> is a two\u2011channel portable instrument that handles single\u2011plane and two\u2011plane dynamic balancing, plus vibration analysis (overall velocity, spectra, waveform). It ships as a complete kit:<\/p>\n\n<ul class=\"db-inline-list\">\n <li>2\u00d7 piezoelectric vibration sensors with magnetic mounts<\/li>\n <li>Laser tachometer (non\u2011contact RPM sensor) with reflective tape<\/li>\n <li>USB measuring unit (connects to any Windows laptop)<\/li>\n <li>Software: balancing wizard, vibration meter, spectrum analyser<\/li>\n <li>Carrying case with all cables and accessories<\/li>\n<\/ul>\n\n<p>RPM range: 300\u2013100,000. Vibration range: 0.5\u201380 mm\/s RMS. Phase accuracy: \u00b11\u00b0. Weight splitting, trim runs, tolerance checking, and report generation included in the software. Full kit weighs 3.5 kg.<\/p>\n\n<div class=\"db-cta\">\n <div class=\"db-cta__title\">Balanset\u20111A \u2014 Portable Balancer & Vibration Analyser<\/div>\n <div class=\"db-cta__text\">Two channels. Two planes. One instrument for field balancing, vibration measurement, and ISO tolerance verification.<\/div>\n <div class=\"db-cta__price\">\u20ac1,975<\/div>\n <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\" class=\"db-cta__btn\">Order Now<\/a>\n <a href=\"https:\/\/wa.me\/351927292960\" class=\"db-cta__btn db-cta__btn--whatsapp\" target=\"_blank\" rel=\"noopener\">Ask via WhatsApp<\/a>\n<\/div>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.jpg\" alt=\"Balanset-1A portable balancer and vibration analyzer \u2014 complete kit with sensors, tachometer, and carrying case\" width=\"750\" height=\"500\" style=\"display:block; margin:24px auto;\">\n\n\n<div class=\"db-author\">\n <div class=\"db-author__avatar\">NS<\/div>\n <div>\n <div class=\"db-author__name\">Nikolai Shelkovenko<\/div>\n <div class=\"db-author__role\">CEO & Field Engineer \u00b7 Vibromera<\/div>\n <div class=\"db-author__bio\">13+ years in vibration diagnostics and field balancing. Personally balanced 2,000+ rotors across mulchers, fans, crushers, centrifuges, and combine harvesters in 20+ countries.<\/div>\n <\/div>\n<\/div>\n\n\n<div class=\"db-back\">\n <a href=\"https:\/\/vibromera.eu\/knowledge-base\/\">\u2190 Back to Knowledge Base<\/a>\n<\/div>\n\n<\/main>\n<\/div>\n\n<\/div>\n<\/body>\n<\/html><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Dynamic Shaft Balancing Instruction \u2013 ISO 21940 | Vibromera Home \u203a Knowledge Base \u203a Dynamic Shaft Balancing Instruction Field Balancing \u00b7 Complete Guide Dynamic Shaft Balancing Instruction: Static vs Dynamic, Field Procedure & ISO 21940 Grades Everything a field engineer needs to balance rotors on-site \u2014 from the physics of unbalance to […]<\/p>\n","protected":false},"author":2,"featured_media":3695,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ai_generated_summary":"","footnotes":""},"categories":[4,8,10,7,9],"tags":[15,23,20,22],"class_list":["post-4224","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-example","category-crashers","category-impellers","category-mulchers","category-rotors","tag-balancing","tag-field-balancing","tag-impeller","tag-portable-balancer"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts\/4224","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/comments?post=4224"}],"version-history":[{"count":4,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts\/4224\/revisions"}],"predecessor-version":[{"id":101650,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts\/4224\/revisions\/101650"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/media\/3695"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/media?parent=4224"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/categories?post=4224"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/tags?post=4224"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

\n\n\n\n\n\nDynamic Shaft Balancing Instruction \u2013 ISO 21940 | Vibromera<\/title>\n<meta name=\"description\" content=\"Dynamic shaft balancing instruction: 7-step two-plane procedure, trial weight formula, ISO 21940 G-grades, correction angles. Field data: 12.4 \u2192 0.8 mm\/s.\">\n<meta name=\"keywords\" content=\"dynamic shaft balancing instruction, dynamic balancing, static balancing, rotor balancing, field balancing, two-plane balancing, single-plane balancing, trial weight calculation, correction weight, vibration analyzer, ISO 1940, ISO 21940, balance quality grade, fan balancing, shaft balancing, Balanset-1A\">\n<meta name=\"author\" content=\"Nikolai Shelkovenko\">\n<meta name=\"robots\" content=\"index, follow, max-image-preview:large, max-snippet:-1\">\n\n\n\n\n\n\n\n\n\n\n\n\n<meta name=\"geo.region\" content=\"EE\">\n<meta name=\"geo.placename\" content=\"Tallinn\">\n<meta name=\"geo.position\" content=\"59.437;24.7536\">\n<meta name=\"ICBM\" content=\"59.437, 24.7536\">\n\n\n<meta property=\"og:type\" content=\"article\">\n<meta property=\"og:url\" content=\"https:\/\/vibromera.eu\/example\/dynamic-shaft-balancing-instruction\/\">\n<meta property=\"og:title\" content=\"Dynamic Shaft Balancing Instruction: Field Procedure, ISO 21940 Grades\">\n<meta property=\"og:description\" content=\"Dynamic shaft balancing instruction. 7-step field procedure, trial weight formula, ISO grades, correction planes. Real data: 12.4 \u2192 0.8 mm\/s.\">\n<meta property=\"og:image\" content=\"https:\/\/vibromera.eu\/wp-content\/uploads\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.jpg\">\n<meta property=\"og:image:width\" content=\"1024\">\n<meta property=\"og:image:height\" content=\"683\">\n<meta property=\"og:image:alt\" content=\"Balanset-1A portable balancer and vibration analyzer \u2014 complete kit\">\n<meta property=\"og:site_name\" content=\"Vibromera\">\n<meta property=\"og:locale\" content=\"en_US\">\n<meta property=\"og:locale:alternate\" content=\"de_DE\">\n<meta property=\"og:locale:alternate\" content=\"es_ES\">\n<meta property=\"og:locale:alternate\" content=\"fr_FR\">\n<meta property=\"og:locale:alternate\" content=\"pt_PT\">\n<meta property=\"og:locale:alternate\" content=\"ru_RU\">\n<meta property=\"article:published_time\" content=\"2024-03-15T00:00:00+00:00\">\n<meta property=\"article:modified_time\" content=\"2026-02-11T00:00:00+00:00\">\n<meta property=\"article:author\" content=\"https:\/\/vibromera.eu\/author\/nikolai\/\">\n<meta property=\"article:section\" content=\"Knowledge Base\">\n<meta property=\"article:tag\" content=\"dynamic balancing\">\n<meta property=\"article:tag\" content=\"shaft balancing\">\n<meta property=\"article:tag\" content=\"ISO 21940\">\n<meta property=\"article:tag\" content=\"field balancing\">\n<meta property=\"article:tag\" content=\"Balanset-1A\">\n\n\n<meta name=\"twitter:card\" content=\"summary_large_image\">\n<meta name=\"twitter:title\" content=\"Dynamic Shaft Balancing Instruction | Field Guide with ISO 21940\">\n<meta name=\"twitter:description\" content=\"Static vs dynamic balance, 7-step procedure, trial weight calculation, G-grade table. Field data included.\">\n<meta name=\"twitter:image\" content=\"https:\/\/vibromera.eu\/wp-content\/uploads\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.jpg\">\n<meta name=\"twitter:image:alt\" content=\"Balanset-1A portable balancer and vibration analyzer \u2014 complete kit\">\n\n\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"TechArticle\",\n \"headline\": \"Dynamic Shaft Balancing Instruction: Static vs Dynamic Balance, Field Procedure & ISO 21940 Grades\",\n \"description\": \"Dynamic shaft balancing instruction for field engineers. Covers static vs dynamic balance physics, types of unbalance, 7-step two-plane balancing procedure, trial weight calculation, angle measurement, ISO 21940-11 balance quality grades, and correction plane placement.\",\n \"author\": {\n \"@type\": \"Person\",\n \"name\": \"Nikolai Shelkovenko\",\n \"jobTitle\": \"CEO & Field Engineer\",\n \"worksFor\": {\n \"@type\": \"Organization\",\n \"name\": \"Vibromera\",\n \"url\": \"https:\/\/vibromera.eu\"\n }\n },\n \"publisher\": {\n \"@type\": \"Organization\",\n \"name\": \"Vibromera\",\n \"url\": \"https:\/\/vibromera.eu\",\n \"logo\": {\n \"@type\": \"ImageObject\",\n \"url\": \"https:\/\/vibromera.eu\/wp-content\/uploads\/vibromera-logo.png\"\n }\n },\n \"datePublished\": \"2024-03-15\",\n \"dateModified\": \"2026-02-11\",\n \"mainEntityOfPage\": \"https:\/\/vibromera.eu\/example\/dynamic-shaft-balancing-instruction\/\",\n \"about\": [\n { \"@type\": \"Thing\", \"name\": \"Dynamic balancing\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q1227750\" },\n { \"@type\": \"Thing\", \"name\": \"Rotor (electric)\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q193881\" },\n { \"@type\": \"Thing\", \"name\": \"Vibration\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q3695508\" },\n { \"@type\": \"Thing\", \"name\": \"ISO 1940\", \"sameAs\": \"https:\/\/www.wikidata.org\/wiki\/Q28134046\" }\n ],\n \"speakable\": {\n \"@type\": \"SpeakableSpecification\",\n \"cssSelector\": [\".db-hero__subtitle\", \".db-definition__text\"]\n },\n \"proficiencyLevel\": \"Expert\",\n \"dependencies\": \"Vibration sensor (accelerometer), laser tachometer or reflective marker, portable balancing instrument\"\n}\n<\/script>\n\n\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"HowTo\",\n \"name\": \"How to Perform Two-Plane Dynamic Balancing in the Field\",\n \"description\": \"Step-by-step procedure for field balancing a rotor using a portable vibration analyzer with two-plane capability.\",\n \"totalTime\": \"PT45M\",\n \"tool\": [\n { \"@type\": \"HowToTool\", \"name\": \"Portable balancing instrument (e.g. Balanset-1A)\" },\n { \"@type\": \"HowToTool\", \"name\": \"Two vibration sensors (accelerometers)\" },\n { \"@type\": \"HowToTool\", \"name\": \"Laser tachometer or reflective tape + optical sensor\" },\n { \"@type\": \"HowToTool\", \"name\": \"Set of trial weights (bolts, washers, hose clamps)\" },\n { \"@type\": \"HowToTool\", \"name\": \"Angle-measuring tool or protractor\" },\n { \"@type\": \"HowToTool\", \"name\": \"Welding equipment or hose clamps for weight attachment\" }\n ],\n \"step\": [\n {\n \"@type\": \"HowToStep\",\n \"position\": 1,\n \"name\": \"Prepare the rotor and mount sensors\",\n \"text\": \"Clean bearing housings. Mount vibration sensor 1 near Plane 1 (drive end) and sensor 2 near Plane 2 (non-drive end). Attach reflective tape to the shaft for the tachometer. Connect all sensors to the balancing instrument.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 2,\n \"name\": \"Measure initial vibration\",\n \"text\": \"Start the rotor and let it reach stable operating speed. Record vibration amplitude and phase at both sensors. This is the baseline measurement.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 3,\n \"name\": \"Install trial weight in Plane 1\",\n \"text\": \"Stop the rotor. Attach a trial weight of known mass at an arbitrary angular position in Plane 1. Mark the position. Restart the rotor and record vibration at both sensors.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 4,\n \"name\": \"Move trial weight to Plane 2\",\n \"text\": \"Stop the rotor. Remove the trial weight from Plane 1 and attach it at an arbitrary angular position in Plane 2. Restart the rotor and record vibration at both sensors.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 5,\n \"name\": \"Calculate correction weights\",\n \"text\": \"The instrument uses the three measurements (baseline + two trial runs) to compute influence coefficients and determine the mass and angle of correction weights needed in both planes.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 6,\n \"name\": \"Install correction weights\",\n \"text\": \"Attach the calculated correction weights at the specified angles in Plane 1 and Plane 2. Measure angles from the trial weight position in the direction of rotation.\"\n },\n {\n \"@type\": \"HowToStep\",\n \"position\": 7,\n \"name\": \"Verify balance\",\n \"text\": \"Start the rotor and measure final vibration. Confirm that residual vibration is below the acceptable threshold per ISO 21940-11. If not, perform a trim run.\"\n }\n ]\n}\n<\/script>\n\n\n<script type=\"application\/ld+json\">{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"Product\",\n \"name\": \"Balanset-1A\",\n \"description\": \"Portable 2-channel dynamic balancing instrument and vibration analyzer for field balancing of rotors in one or two planes.\",\n \"brand\": {\n \"@type\": \"Brand\",\n \"name\": \"Vibromera\"\n },\n \"manufacturer\": {\n \"@type\": \"Organization\",\n \"name\": \"Vibromera\",\n \"url\": \"https:\/\/vibromera.eu\"\n },\n \"url\": \"https:\/\/vibromera.eu\/product\/balanset-1\/\",\n \"offers\": {\n \"@type\": \"Offer\",\n \"price\": \"1975.00\",\n \"priceCurrency\": \"EUR\",\n \"priceValidUntil\": \"2026-12-31\",\n \"availability\": \"https:\/\/schema.org\/InStock\",\n \"url\": \"https:\/\/vibromera.eu\/product\/balanset-1\/\"\n },\n \"additionalProperty\": [\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Number of channels\",\n \"value\": \"2\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Balancing planes\",\n \"value\": \"1 or 2\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Vibration measurement range\",\n \"value\": \"0.5\u201380 mm\/s RMS\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Frequency range\",\n \"value\": \"5\u2013550 Hz\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"RPM range\",\n \"value\": \"300\u2013100,000\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Phase measurement accuracy\",\n \"value\": \"\u00b11\u00b0\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Sensor type\",\n \"value\": \"Piezoelectric accelerometer\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Software\",\n \"value\": \"Balanset-1A (Windows)\"\n },\n {\n \"@type\": \"PropertyValue\",\n \"name\": \"Weight\",\n \"value\": \"3.5 kg (complete kit)\"\n }\n ]\n}<\/script>\n\n\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"FAQPage\",\n \"mainEntity\": [\n {\n \"@type\": \"Question\",\n \"name\": \"What is the difference between static and dynamic balancing?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Static balancing corrects unbalance in a single plane \u2014 the rotor's centre of gravity is shifted back to the rotation axis. It works for narrow, disc-shaped parts (diameter-to-width ratio greater than 7:1). Dynamic balancing corrects unbalance in two planes simultaneously, addressing both force and couple unbalance. It is required for any elongated rotor where masses are distributed along the shaft length.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"How do I calculate trial weight mass for field balancing?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Use the formula: Mt = Mr \u00d7 K \/ (Rt \u00d7 (N\/100)\u00b2), where Mr is rotor mass (g), K is support stiffness coefficient (1 = soft, 3 = average, 5 = rigid), Rt is trial weight installation radius (cm), and N is RPM. The trial weight should produce at least 20\u201330% amplitude change or 20\u201330\u00b0 phase shift. Use our online trial weight calculator at vibromera.eu\/trial-weight-mass-calculator\/ for instant results. At low RPM (below 500), use the 10% static rule: trial mass = 10% of rotor mass \/ correction radius.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"When should I use single-plane vs two-plane balancing?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Use single-plane (static) balancing for narrow disc-shaped rotors where the diameter is more than 7 times the width \u2014 flywheels, grinding wheels, saw blades. Use two-plane (dynamic) balancing for elongated rotors \u2014 shafts, fans with wide impellers, mulcher rotors, rolls. If in doubt, two-plane balancing is always the safer choice.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"What ISO standard covers rotor balancing tolerances?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"ISO 21940-11:2016 is the current standard for rigid rotor balancing. It replaced the older ISO 1940-1:2003. It defines balance quality grades (G0.4 to G4000) that specify the maximum permissible residual specific unbalance based on rotor type and operating speed. Common grades include G6.3 for fans and pumps, G2.5 for electric motors, and G1.0 for turbocharger rotors.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"How do I measure the angle for correction weight placement?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"The balancing instrument calculates the correction angle relative to the trial weight position. Mark where you placed the trial weight (this is your 0\u00b0 reference). Then measure the indicated angle in the direction of rotor rotation from that reference point. The correction weight goes at the resulting position. If the instrument says to remove weight, place it 180\u00b0 opposite.\"\n }\n },\n {\n \"@type\": \"Question\",\n \"name\": \"Can I balance a rotor without removing it from the machine?\",\n \"acceptedAnswer\": {\n \"@type\": \"Answer\",\n \"text\": \"Yes \u2014 this is called field balancing or in-situ balancing. You mount vibration sensors on the bearing housings, attach a tachometer reference, and run the machine at operating speed. A portable instrument like the Balanset-1A guides you through the trial weight sequence and calculates corrections. Field balancing saves hours of disassembly time and eliminates alignment errors from reinstallation.\"\n }\n }\n ]\n}\n<\/script>\n\n\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"BreadcrumbList\",\n \"itemListElement\": [\n { \"@type\": \"ListItem\", \"position\": 1, \"name\": \"Home\", \"item\": \"https:\/\/vibromera.eu\/\" },\n { \"@type\": \"ListItem\", \"position\": 2, \"name\": \"Knowledge Base\", \"item\": \"https:\/\/vibromera.eu\/knowledge-base\/\" },\n { \"@type\": \"ListItem\", \"position\": 3, \"name\": \"Dynamic Shaft Balancing Instruction\", \"item\": \"https:\/\/vibromera.eu\/example\/dynamic-shaft-balancing-instruction\/\" }\n ]\n}\n<\/script>\n\n<style>\n\/* ============================================\n NAMESPACE: db- (dynamic-balancing)\n PALETTE: Forest #1a3c34 + Burnt Orange #d4622b\n ISOLATION: all rules scoped to .db-article\n ============================================ *\/\n@import url('https:\/\/fonts.googleapis.com\/css2?family=Bitter:wght@400;600;700&family=Source+Sans+3:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');\n\n.db-article {\n --db-forest: #1a3c34;\n --db-forest-light: #264d43;\n --db-forest-dark: #0f2920;\n --db-orange: #d4622b;\n --db-orange-light: #e8844f;\n --db-orange-glow: rgba(212,98,43,0.12);\n --db-cream: #faf6f1;\n --db-warm-white: #fefcf9;\n --db-sand: #f0e9df;\n --db-text: #2c2418;\n --db-text-light: #6b5e4f;\n --db-border: #d9cfc2;\n --db-success: #2d8a56;\n --db-warning: #c49a1a;\n --db-danger: #c44d3f;\n --db-code-bg: #f5f0e8;\n\n font-family: 'Source Sans 3', 'Segoe UI', sans-serif;\n color: var(--db-text);\n background: var(--db-warm-white);\n line-height: 1.72;\n font-size: 17px;\n -webkit-font-smoothing: antialiased;\n box-sizing: border-box;\n}\n\n.db-article *, .db-article *::before, .db-article *::after { box-sizing: border-box; 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height: 400px;\n background: radial-gradient(circle, rgba(212,98,43,0.08) 0%, transparent 70%);\n border-radius: 50%;\n pointer-events: none;\n}\n.db-hero__inner {\n max-width: 1400px;\n margin: 0 auto;\n position: relative;\n z-index: 1;\n}\n.db-hero__badge {\n display: inline-block;\n background: rgba(212,98,43,0.2);\n border: 1px solid rgba(212,98,43,0.4);\n color: var(--db-orange-light);\n font-size: 12px;\n font-weight: 600;\n letter-spacing: 0.08em;\n text-transform: uppercase;\n padding: 0.35em 1em;\n border-radius: 4px;\n margin-bottom: 19px;\n}\n.db-hero__title {\n font-family: 'Bitter', Georgia, serif;\n font-size: clamp(32px, 4.5vw, 51px);\n font-weight: 700;\n line-height: 1.15;\n margin-bottom: 16px;\n max-width: 900px;\n}\n.db-hero__title em {\n font-style: normal;\n color: var(--db-orange-light);\n}\n.db-hero__subtitle {\n font-size: clamp(17px, 2vw, 20px);\n line-height: 1.6;\n opacity: 0.92;\n max-width: 720px;\n margin-bottom: 24px;\n}\n.db-hero__meta {\n display: flex;\n gap: 32px;\n flex-wrap: wrap;\n font-size: 14px;\n opacity: 0.7;\n}\n.db-hero__meta-item { display: flex; align-items: center; gap: 0.4em; }\n\n\/* ---- LAYOUT GRID ---- *\/\n.db-layout {\n max-width: 1400px;\n margin: 0 auto;\n padding: 40px 32px 64px;\n display: grid;\n grid-template-columns: 260px 1fr;\n gap: 48px;\n}\n\n\/* ---- TOC SIDEBAR ---- *\/\n.db-toc {\n position: sticky;\n top: 32px;\n align-self: start;\n max-height: calc(100vh - 64px);\n overflow-y: auto;\n padding-right: 16px;\n}\n.db-toc__title {\n font-family: 'Bitter', serif;\n font-size: 13px;\n font-weight: 700;\n text-transform: uppercase;\n letter-spacing: 0.1em;\n color: var(--db-forest);\n margin-bottom: 16px;\n padding-bottom: 8px;\n border-bottom: 2px solid var(--db-orange);\n}\n.db-toc__list {\n list-style: none;\n counter-reset: toc-counter;\n}\n.db-toc__item {\n counter-increment: toc-counter;\n margin-bottom: 2px;\n}\n.db-toc__link {\n display: flex;\n align-items: baseline;\n gap: 0.6em;\n padding: 0.45em 0.6em;\n border-radius: 4px;\n text-decoration: none;\n color: var(--db-text-light);\n font-size: 14px;\n font-weight: 500;\n line-height: 1.35;\n transition: all 0.15s ease;\n}\n.db-toc__link::before {\n content: counter(toc-counter, decimal-leading-zero);\n font-family: 'JetBrains Mono', monospace;\n font-size: 12px;\n font-weight: 500;\n color: var(--db-orange);\n min-width: 1.6em;\n}\n.db-toc__link:hover {\n background: var(--db-orange-glow);\n color: var(--db-forest);\n}\n\n\/* ---- CONTENT AREA ---- *\/\n.db-content {\n min-width: 0;\n}\n.db-content h2 {\n font-family: 'Bitter', Georgia, serif;\n font-size: clamp(24px, 3vw, 30px);\n font-weight: 700;\n color: var(--db-forest);\n margin: 48px 0 19px;\n padding-top: 16px;\n line-height: 1.25;\n}\n.db-content h2:first-child { margin-top: 0; }\n.db-content h3 {\n font-family: 'Bitter', serif;\n font-size: 19px;\n font-weight: 600;\n color: var(--db-forest-light);\n margin: 32px 0 13px;\n}\n.db-content p {\n margin-bottom: 16px;\n}\n.db-content img {\n max-width: 100%;\n height: auto;\n border-radius: 8px;\n margin: 24px 0;\n display: block;\n}\n\n\/* ---- DEFINITION BLOCK ---- *\/\n.db-definition {\n background: var(--db-cream);\n border-left: 4px solid var(--db-orange);\n border-radius: 0 8px 8px 0;\n padding: 29px 32px;\n margin-bottom: 32px;\n}\n.db-definition__label {\n font-family: 'JetBrains Mono', monospace;\n font-size: 12px;\n font-weight: 500;\n text-transform: uppercase;\n letter-spacing: 0.1em;\n color: var(--db-orange);\n margin-bottom: 8px;\n}\n.db-definition__text {\n font-size: 17px;\n line-height: 1.7;\n color: var(--db-text);\n}\n\n\/* ---- COMPARISON CARDS ---- *\/\n.db-compare {\n display: grid;\n grid-template-columns: 1fr 1fr;\n gap: 24px;\n margin: 32px 0;\n}\n.db-compare__card {\n background: var(--db-cream);\n border-radius: 10px;\n padding: 29px;\n border: 1px solid var(--db-border);\n position: relative;\n}\n.db-compare__card--static {\n border-top: 3px solid var(--db-warning);\n}\n.db-compare__card--dynamic {\n border-top: 3px solid var(--db-orange);\n}\n.db-compare__badge {\n display: inline-block;\n font-family: 'JetBrains Mono', monospace;\n font-size: 11px;\n font-weight: 500;\n text-transform: uppercase;\n letter-spacing: 0.08em;\n padding: 0.25em 0.7em;\n border-radius: 3px;\n margin-bottom: 13px;\n}\n.db-compare__card--static .db-compare__badge {\n background: rgba(196,154,26,0.12);\n color: var(--db-warning);\n}\n.db-compare__card--dynamic .db-compare__badge {\n background: var(--db-orange-glow);\n color: var(--db-orange);\n}\n.db-compare__title {\n font-family: 'Bitter', serif;\n font-size: 20px;\n font-weight: 700;\n color: var(--db-forest);\n margin-bottom: 13px;\n}\n.db-compare__text {\n font-size: 15px;\n line-height: 1.65;\n color: var(--db-text);\n}\n.db-compare__text strong {\n color: var(--db-forest);\n}\n.db-compare__img {\n width: 100%;\n border-radius: 6px;\n margin-bottom: 16px;\n}\n\n\/* ---- ENGINEER NOTE ---- *\/\n.db-note {\n background: linear-gradient(135deg, var(--db-forest-dark), var(--db-forest));\n color: #fff;\n border-radius: 8px;\n padding: 24px 29px;\n margin: 29px 0;\n position: relative;\n}\n.db-note::before {\n content: '\u2699';\n position: absolute;\n top: -10px; left: 16px;\n background: var(--db-orange);\n color: #fff;\n width: 28px; height: 28px;\n border-radius: 50%;\n display: flex;\n align-items: center;\n justify-content: center;\n font-size: 14px;\n}\n.db-note__title {\n font-family: 'Bitter', serif;\n font-size: 14px;\n font-weight: 700;\n text-transform: uppercase;\n letter-spacing: 0.06em;\n color: var(--db-orange-light);\n margin-bottom: 6px;\n}\n.db-note__text {\n font-size: 15px;\n line-height: 1.6;\n opacity: 0.95;\n}\n\n\/* ---- TABLE ---- *\/\n.db-table-wrap {\n overflow-x: auto;\n margin: 24px 0;\n border-radius: 8px;\n border: 1px solid var(--db-border);\n}\n.db-table {\n width: 100%;\n border-collapse: collapse;\n font-size: 14px;\n}\n.db-table thead {\n background: var(--db-forest);\n color: #fff;\n}\n.db-table th {\n padding: 13px 16px;\n text-align: left;\n font-weight: 600;\n font-size: 13px;\n text-transform: uppercase;\n letter-spacing: 0.04em;\n}\n.db-table td {\n padding: 11px 16px;\n border-bottom: 1px solid var(--db-border);\n vertical-align: top;\n}\n.db-table tbody tr:nth-child(even) {\n background: var(--db-cream);\n}\n.db-table tbody tr:hover {\n background: var(--db-orange-glow);\n}\n.db-table code {\n font-family: 'JetBrains Mono', monospace;\n font-size: 13px;\n background: var(--db-code-bg);\n padding: 0.15em 0.4em;\n border-radius: 3px;\n}\n\n\/* ---- STEPS TIMELINE ---- *\/\n.db-steps {\n margin: 32px 0;\n position: relative;\n}\n.db-step {\n display: grid;\n grid-template-columns: 52px 1fr;\n gap: 19px;\n margin-bottom: 24px;\n position: relative;\n}\n.db-step::before {\n content: '';\n position: absolute;\n left: 25px;\n top: 52px;\n bottom: -1.80px;\n width: 2px;\n background: var(--db-border);\n}\n.db-step:last-child::before { display: none; }\n\n.db-step__number {\n width: 52px;\n height: 52px;\n background: var(--db-forest);\n color: var(--db-orange-light);\n border-radius: 50%;\n display: flex;\n align-items: center;\n justify-content: center;\n font-family: 'JetBrains Mono', monospace;\n font-size: 18px;\n font-weight: 700;\n flex-shrink: 0;\n position: relative;\n z-index: 1;\n}\n.db-step__body {\n background: var(--db-cream);\n border-radius: 8px;\n padding: 21px 24px;\n border: 1px solid var(--db-border);\n}\n.db-step__title {\n font-family: 'Bitter', serif;\n font-size: 17px;\n font-weight: 700;\n color: var(--db-forest);\n margin-bottom: 6px;\n}\n.db-step__text {\n font-size: 15px;\n line-height: 1.65;\n color: var(--db-text);\n}\n.db-step__tip {\n margin-top: 10px;\n padding-top: 10px;\n border-top: 1px dashed var(--db-border);\n font-size: 14px;\n color: var(--db-orange);\n font-weight: 500;\n}\n.db-step__img {\n width: 100%;\n border-radius: 6px;\n margin-top: 13px;\n}\n\n\/* ---- FORMULA BLOCK ---- *\/\n.db-formula {\n background: var(--db-code-bg);\n border: 1px solid var(--db-border);\n border-radius: 8px;\n padding: 24px 32px;\n margin: 24px 0;\n text-align: center;\n}\n.db-formula__label {\n font-family: 'JetBrains Mono', monospace;\n font-size: 12px;\n text-transform: uppercase;\n letter-spacing: 0.1em;\n color: var(--db-text-light);\n margin-bottom: 13px;\n}\n.db-formula__expression {\n font-family: 'JetBrains Mono', monospace;\n font-size: 18px;\n font-weight: 500;\n color: var(--db-forest);\n margin-bottom: 13px;\n}\n.db-formula__legend {\n font-size: 14px;\n color: var(--db-text-light);\n text-align: left;\n line-height: 1.7;\n}\n\n\/* ---- FAQ ACCORDION ---- *\/\n.db-faq {\n margin: 32px 0;\n}\n.db-faq__item {\n border: 1px solid var(--db-border);\n border-radius: 8px;\n margin-bottom: 10px;\n overflow: hidden;\n}\n.db-faq__question {\n width: 100%;\n background: var(--db-cream);\n border: none;\n padding: 18px 24px;\n font-family: 'Source Sans 3', sans-serif;\n font-size: 16px;\n font-weight: 600;\n color: var(--db-forest);\n text-align: left;\n cursor: pointer;\n display: flex;\n justify-content: space-between;\n align-items: center;\n transition: background 0.15s;\n}\n.db-faq__question:hover { background: var(--db-sand); }\n.db-faq__question::after {\n content: '+';\n font-family: 'JetBrains Mono', monospace;\n font-size: 19px;\n color: var(--db-orange);\n flex-shrink: 0;\n margin-left: 16px;\n transition: transform 0.2s;\n}\n.db-faq__item.open .db-faq__question::after {\n content: '\u2212';\n}\n.db-faq__answer {\n max-height: 0;\n overflow: hidden;\n transition: max-height 0.3s ease;\n}\n.db-faq__item.open .db-faq__answer {\n max-height: 500px;\n}\n.db-faq__answer-inner {\n padding: 0 24px 21px;\n font-size: 15px;\n line-height: 1.7;\n color: var(--db-text);\n}\n\n\/* ---- FIELD REPORT CARD ---- *\/\n.db-field-report {\n background: linear-gradient(135deg, var(--db-forest-dark) 0%, var(--db-forest) 100%);\n color: #fff;\n border-radius: 10px;\n padding: 32px 35px;\n margin: 40px 0;\n}\n.db-field-report__badge {\n display: inline-block;\n font-family: 'JetBrains Mono', monospace;\n font-size: 11px;\n text-transform: uppercase;\n letter-spacing: 0.1em;\n color: var(--db-orange-light);\n background: rgba(212,98,43,0.2);\n padding: 0.3em 0.8em;\n border-radius: 3px;\n margin-bottom: 16px;\n}\n.db-field-report__title {\n font-family: 'Bitter', serif;\n font-size: 21px;\n font-weight: 700;\n margin-bottom: 16px;\n}\n.db-field-report__grid {\n display: grid;\n grid-template-columns: 1fr 1fr;\n gap: 16px;\n margin-bottom: 16px;\n}\n.db-field-report__stat {\n background: rgba(255,255,255,0.08);\n border-radius: 6px;\n padding: 16px;\n}\n.db-field-report__label {\n font-size: 12px;\n text-transform: uppercase;\n letter-spacing: 0.06em;\n opacity: 0.7;\n margin-bottom: 5px;\n}\n.db-field-report__value {\n font-family: 'JetBrains Mono', monospace;\n font-size: 22px;\n font-weight: 700;\n}\n.db-field-report__value--before { color: var(--db-danger); }\n.db-field-report__value--after { color: var(--db-success); }\n.db-field-report__detail {\n font-size: 14px;\n line-height: 1.65;\n opacity: 0.9;\n}\n\n\/* ---- CTA ---- *\/\n.db-cta {\n background: var(--db-cream);\n border: 2px solid var(--db-orange);\n border-radius: 10px;\n padding: 32px 35px;\n margin: 40px 0;\n text-align: center;\n}\n.db-cta__title {\n font-family: 'Bitter', serif;\n font-size: 21px;\n font-weight: 700;\n color: var(--db-forest);\n margin-bottom: 8px;\n}\n.db-cta__text {\n font-size: 15px;\n color: var(--db-text-light);\n margin-bottom: 19px;\n max-width: 500px;\n margin-left: auto;\n margin-right: auto;\n}\n.db-cta__price {\n font-family: 'JetBrains Mono', monospace;\n font-size: 26px;\n font-weight: 700;\n color: var(--db-orange);\n margin-bottom: 16px;\n}\n.db-cta__btn {\n display: inline-block;\n background: var(--db-orange) !important;\n color: #ffffff !important;\n text-decoration: none !important;\n padding: 14px 36px;\n border-radius: 6px;\n font-weight: 700;\n font-size: 16px;\n letter-spacing: 0.02em;\n transition: background 0.2s, transform 0.1s;\n border: 2px solid var(--db-orange);\n}\n.db-article a.db-cta__btn,\n.db-article a.db-cta__btn:visited,\n.db-article a.db-cta__btn:link,\n.db-content a.db-cta__btn,\n.db-content a.db-cta__btn:visited,\n.db-content a.db-cta__btn:link {\n color: #ffffff !important;\n text-decoration: none !important;\n}\n.db-cta__btn:hover {\n background: var(--db-orange-light) !important;\n border-color: var(--db-orange-light);\n transform: translateY(-1px);\n color: #ffffff !important;\n}\n.db-cta__btn--whatsapp {\n background: #25d366 !important;\n border-color: #25d366;\n margin-left: 13px;\n}\n.db-article a.db-cta__btn--whatsapp,\n.db-article a.db-cta__btn--whatsapp:visited,\n.db-content a.db-cta__btn--whatsapp,\n.db-content a.db-cta__btn--whatsapp:visited {\n color: #ffffff !important;\n}\n.db-cta__btn--whatsapp:hover { background: #20bd5a !important; border-color: #20bd5a; }\n\n\/* ---- AUTHOR ---- *\/\n.db-author {\n display: flex;\n gap: 19px;\n align-items: center;\n padding: 32px;\n background: var(--db-cream);\n border-radius: 10px;\n border: 1px solid var(--db-border);\n margin: 48px 0 16px;\n}\n.db-author__avatar {\n width: 64px; height: 64px;\n background: var(--db-forest);\n color: var(--db-orange-light);\n border-radius: 50%;\n display: flex;\n align-items: center;\n justify-content: center;\n font-family: 'Bitter', serif;\n font-size: 24px;\n font-weight: 700;\n flex-shrink: 0;\n}\n.db-author__name {\n font-family: 'Bitter', serif;\n font-weight: 700;\n color: var(--db-forest);\n font-size: 16px;\n}\n.db-author__role {\n font-size: 14px;\n color: var(--db-text-light);\n}\n.db-author__bio {\n font-size: 14px;\n color: var(--db-text-light);\n line-height: 1.55;\n}\n\n\/* ---- BACK LINK ---- *\/\n.db-back {\n text-align: center;\n padding: 32px;\n}\n.db-back a {\n color: var(--db-forest);\n text-decoration: none;\n font-weight: 600;\n font-size: 14px;\n}\n.db-back a:hover { color: var(--db-orange); }\n\n\/* ---- APPLICATIONS TABLE ---- *\/\n.db-app-cards {\n display: grid;\n grid-template-columns: 1fr 1fr;\n gap: 16px;\n margin: 24px 0;\n}\n.db-app-card {\n background: var(--db-cream);\n border-radius: 8px;\n padding: 21px 24px;\n border: 1px solid var(--db-border);\n border-left: 3px solid var(--db-orange);\n}\n.db-app-card__title {\n font-family: 'Bitter', serif;\n font-weight: 700;\n font-size: 16px;\n color: var(--db-forest);\n margin-bottom: 6px;\n}\n.db-app-card__specs {\n font-family: 'JetBrains Mono', monospace;\n font-size: 12px;\n color: var(--db-orange);\n margin-bottom: 6px;\n}\n.db-app-card__text {\n font-size: 14px;\n line-height: 1.55;\n color: var(--db-text);\n}\n\n\/* ---- RESPONSIVE ---- *\/\n@media (max-width: 960px) {\n .db-layout {\n grid-template-columns: 1fr;\n padding: 24px 19px 48px;\n }\n .db-toc {\n position: static;\n max-height: none;\n padding-right: 0;\n margin-bottom: 16px;\n }\n .db-toc__list {\n display: grid;\n grid-template-columns: 1fr 1fr;\n gap: 3px 16px;\n }\n .db-compare { grid-template-columns: 1fr; }\n .db-app-cards { grid-template-columns: 1fr; }\n .db-field-report__grid { grid-template-columns: 1fr 1fr; }\n .db-hero { padding: 48px 24px 40px; }\n}\n@media (max-width: 600px) {\n .db-toc__list { grid-template-columns: 1fr; }\n .db-field-report__grid { grid-template-columns: 1fr; }\n .db-hero__meta { flex-direction: column; gap: 8px; }\n .db-cta__btn { display: block; margin: 8px 0; }\n .db-cta__btn--whatsapp { margin-left: 0; }\n .db-step { grid-template-columns: 42px 1fr; gap: 13px; }\n .db-step__number { width: 42px; height: 42px; font-size: 14px; }\n .db-step::before { left: 20px; }\n .db-author { flex-direction: column; text-align: center; }\n}\n\n\/* ---- PRINT ---- *\/\n@media print {\n .db-toc, .db-cta, .db-hero::before, .db-hero::after { display: none; }\n .db-hero { background: #333 !important; -webkit-print-color-adjust: exact; }\n .db-layout { grid-template-columns: 1fr; }\n .db-content h2 { page-break-before: auto; }\n}\n\n\/* ---- INTERNAL LINKS ---- *\/\n.db-content a {\n color: var(--db-orange);\n text-decoration: underline;\n text-decoration-color: rgba(212,98,43,0.3);\n text-underline-offset: 2px;\n transition: text-decoration-color 0.15s;\n}\n.db-content a:hover {\n text-decoration-color: var(--db-orange);\n}\n\n\/* ---- INLINE LIST ---- *\/\n.db-inline-list {\n list-style: none;\n padding-left: 0;\n}\n.db-inline-list li {\n padding: 6px 0 6px 22px;\n position: relative;\n font-size: 15px;\n}\n.db-inline-list li::before {\n content: '\u25b8';\n position: absolute;\n left: 0;\n color: var(--db-orange);\n font-weight: 700;\n}\n\n\/* ---- WARNING BOX ---- *\/\n.db-warning {\n background: rgba(196,154,26,0.08);\n border-left: 4px solid var(--db-warning);\n border-radius: 0 8px 8px 0;\n padding: 19px 24px;\n margin: 24px 0;\n font-size: 15px;\n line-height: 1.65;\n}\n.db-warning strong {\n color: var(--db-warning);\n}\n\n\/* unbalance types diagram *\/\n.db-unbalance-grid {\n display: grid;\n grid-template-columns: repeat(4, 1fr);\n gap: 16px;\n margin: 24px 0;\n}\n.db-unbalance-card {\n text-align: center;\n background: var(--db-cream);\n border-radius: 8px;\n padding: 19px 13px;\n border: 1px solid var(--db-border);\n}\n.db-unbalance-card__icon {\n width: 64px;\n height: 64px;\n margin: 0 auto 10px;\n display: block;\n}\n.db-unbalance-card__title {\n font-family: 'Bitter', serif;\n font-weight: 700;\n font-size: 14px;\n color: var(--db-forest);\n margin-bottom: 5px;\n}\n.db-unbalance-card__text {\n font-size: 12px;\n color: var(--db-text-light);\n line-height: 1.5;\n}\n\n@media (max-width: 700px) {\n .db-unbalance-grid { grid-template-columns: 1fr 1fr; }\n}\n<\/style>\n<\/head>\n\n<body>\n<div class=\"db-article\">\n\n\n<nav class=\"db-breadcrumb\" aria-label=\"Breadcrumb\">\n <a href=\"https:\/\/vibromera.eu\/\">Home<\/a>\n <span>\u203a<\/span>\n <a href=\"https:\/\/vibromera.eu\/knowledge-base\/\">Knowledge Base<\/a>\n <span>\u203a<\/span>\n Dynamic Shaft Balancing Instruction\n<\/nav>\n\n\n<header class=\"db-hero\">\n <div class=\"db-hero__inner\">\n <div class=\"db-hero__badge\">Field Balancing \u00b7 Complete Guide<\/div>\n <h1 class=\"db-hero__title\">Dynamic Shaft Balancing Instruction: <em>Static vs Dynamic<\/em>, Field Procedure & ISO 21940 Grades<\/h1>\n <p class=\"db-hero__subtitle\">Everything a field engineer needs to balance rotors on-site \u2014 from the physics of unbalance to the final verification run. Seven-step procedure, trial weight formulas, correction angle measurement, and ISO tolerance tables. Tested on 2,000+ rotors across fans, mulchers, crushers, and shafts.<\/p>\n <div class=\"db-hero__meta\">\n <span class=\"db-hero__meta-item\">\u270e Nikolai Shelkovenko<\/span>\n <span class=\"db-hero__meta-item\">Updated: Feb 2026<\/span>\n <span class=\"db-hero__meta-item\">~18 min read<\/span>\n <\/div>\n <\/div>\n<\/header>\n\n\n<div class=\"db-layout\">\n\n\n<aside class=\"db-toc\" aria-label=\"Table of Contents\">\n <div class=\"db-toc__title\">Contents<\/div>\n <ol class=\"db-toc__list\">\n <li class=\"db-toc__item\"><a href=\"#what-is\" class=\"db-toc__link\">What Is Dynamic Balancing<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#static-vs-dynamic\" class=\"db-toc__link\">Static vs Dynamic Balance<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#types-of-unbalance\" class=\"db-toc__link\">Four Types of Unbalance<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#single-vs-two\" class=\"db-toc__link\">Single-Plane vs Two-Plane<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#iso-grades\" class=\"db-toc__link\">ISO 21940-11 Balance Grades<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#field-procedure\" class=\"db-toc__link\">7-Step Field Procedure<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#trial-weight\" class=\"db-toc__link\">Trial Weight Calculation<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#angle-measurement\" class=\"db-toc__link\">Correction Angle Measurement<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#correction-planes\" class=\"db-toc__link\">Correction Planes & Sensors<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#applications\" class=\"db-toc__link\">Applications by Machine Type<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#weight-methods\" class=\"db-toc__link\">Weight Attachment Methods<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#common-mistakes\" class=\"db-toc__link\">Common Mistakes<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#field-report\" class=\"db-toc__link\">Field Report: Mulcher Rotor<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#fan-balancing\" class=\"db-toc__link\">Fan Balancing Walkthrough<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#faq\" class=\"db-toc__link\">FAQ<\/a><\/li>\n <li class=\"db-toc__item\"><a href=\"#equipment\" class=\"db-toc__link\">Equipment<\/a><\/li>\n <\/ol>\n<\/aside>\n\n\n<main class=\"db-content\">\n\n\n<h2 id=\"what-is\">What Is Dynamic Balancing?<\/h2>\n\n<div class=\"db-definition\">\n <div class=\"db-definition__label\">Definition<\/div>\n <p class=\"db-definition__text\"><strong>Dynamic balancing<\/strong> is the process of measuring and correcting the uneven mass distribution of a rotating body (rotor) while it spins at operating speed. Unlike static balancing, which corrects mass offset in a single plane, dynamic balancing addresses imbalance in <strong>two or more planes simultaneously<\/strong>, eliminating both centrifugal force and rocking couple that cause bearing vibration.<\/p>\n<\/div>\n\n<p>Every rotating part \u2014 from a 200 kg mulcher rotor to a 5 g dental drill spindle \u2014 has some residual unbalance. Manufacturing tolerances, material inconsistencies, corrosion, and accumulated deposits shift the mass centre away from the geometric rotation axis. The result is a centrifugal force that grows with the square of speed: double the RPM and the force quadruples.<\/p>\n\n<p>A rotor spinning at 3,000 RPM with just 10 g of unbalance at a 150 mm radius generates roughly 150 N of rotating force \u2014 enough to destroy bearings in weeks. Dynamic balancing reduces this force to a level specified by international standards (ISO 21940‑11, formerly ISO 1940), extending bearing life from months to years and cutting vibration\u2011related downtime.<\/p>\n\n<div class=\"db-note\">\n <div class=\"db-note__title\">Field engineer's note<\/div>\n <div class=\"db-note__text\">In 13 years of field work, unbalance has been the root cause in roughly 40% of the vibration complaints I investigate. It is also the easiest fault to fix on\u2011site \u2014 a trained technician with the right instrument finishes in 30\u201345 minutes without removing the rotor.<\/div>\n<\/div>\n\n\n<h2 id=\"static-vs-dynamic\">Static vs Dynamic Balance<\/h2>\n\n<div class=\"db-compare\">\n <div class=\"db-compare__card db-compare__card--static\">\n <div class=\"db-compare__badge\">Single plane<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-compare__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/\u0420\u043e\u0442\u0435\u0440_statika-1024x549.jpg\" alt=\"Rotor in static imbalance \u2014 heavy point rotates to the bottom\" width=\"750\" height=\"402\">\n <div class=\"db-compare__title\">Static Balance<\/div>\n <div class=\"db-compare__text\">\n <p>The rotor's centre of gravity is offset from the rotation axis in <strong>one plane<\/strong>. When placed on knife\u2011edge supports, the heavy side rolls to the bottom \u2014 you can detect this without spinning.<\/p>\n <p><strong>Correction:<\/strong> add or remove mass at a single angular position opposite the heavy spot. One correction plane is enough.<\/p>\n <p><strong>Applies to:<\/strong> narrow disc\u2011shaped parts where diameter > 7\u00d7 width \u2014 flywheels, grinding wheels, single\u2011disc impellers, saw blades, brake discs.<\/p>\n <\/div>\n <\/div>\n\n <div class=\"db-compare__card db-compare__card--dynamic\">\n <div class=\"db-compare__badge\">Two planes<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-compare__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/long-rotor-1024x549.jpg\" alt=\"Long rotor in dynamic imbalance \u2014 two mass offsets in different planes\" width=\"750\" height=\"402\">\n <div class=\"db-compare__title\">Dynamic Balance<\/div>\n <div class=\"db-compare__text\">\n <p>Two (or more) mass offsets sit in <strong>different planes<\/strong> along the rotor length. They may cancel each other statically \u2014 the rotor sits still on knife\u2011edges \u2014 but create a <strong>rocking couple<\/strong> when spinning. This couple cannot be detected or corrected without rotation.<\/p>\n <p><strong>Correction:<\/strong> two compensating weights in two separate planes. The instrument calculates mass and angle for each plane from the influence coefficient matrix.<\/p>\n <p><strong>Applies to:<\/strong> elongated rotors \u2014 shafts, fans with wide impellers, mulcher rotors, rollers, multi\u2011stage pump impellers, turbines.<\/p>\n <\/div>\n <\/div>\n<\/div>\n\n<div class=\"db-warning\">\n <strong>Key distinction:<\/strong> a statically balanced rotor can still have severe dynamic imbalance. The forces in one plane exactly oppose those in another, so the rotor does not roll on supports \u2014 but the moment it spins, the couple creates violent vibration at the bearings. Two\u2011plane dynamic balancing catches what static methods miss.\n<\/div>\n\n\n<h2 id=\"types-of-unbalance\">Four Types of Unbalance<\/h2>\n\n<p>ISO 21940‑11 distinguishes four fundamental unbalance patterns. Understanding which one dominates helps choose the correct balancing strategy.<\/p>\n\n<div class=\"db-unbalance-grid\">\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"16\" y=\"24\" width=\"32\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"8\" y1=\"32\" x2=\"16\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"48\" y1=\"32\" x2=\"56\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"40\" cy=\"36\" r=\"4\" fill=\"#d4622b\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Static<\/div>\n <div class=\"db-unbalance-card__text\">Single heavy spot. CG displaced parallel to rotation axis. Detectable at rest. Single\u2011plane correction.<\/div>\n <\/div>\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"12\" y=\"24\" width=\"40\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"4\" y1=\"32\" x2=\"12\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"52\" y1=\"32\" x2=\"60\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"20\" cy=\"22\" r=\"3.5\" fill=\"#d4622b\"\/>\n <circle cx=\"44\" cy=\"42\" r=\"3.5\" fill=\"#d4622b\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Couple<\/div>\n <div class=\"db-unbalance-card__text\">Two equal masses 180\u00b0 apart in different planes. Net force = 0, but creates a torque (couple). Invisible at rest.<\/div>\n <\/div>\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"12\" y=\"24\" width=\"40\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"4\" y1=\"32\" x2=\"12\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"52\" y1=\"32\" x2=\"60\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"32\" cy=\"36\" r=\"3\" fill=\"#c49a1a\"\/>\n <circle cx=\"20\" cy=\"22\" r=\"3\" fill=\"#d4622b\"\/>\n <circle cx=\"44\" cy=\"42\" r=\"3\" fill=\"#d4622b\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Quasi\u2011static<\/div>\n <div class=\"db-unbalance-card__text\">Combination of static + couple where principal inertia axis intersects rotation axis at a point other than the CG.<\/div>\n <\/div>\n <div class=\"db-unbalance-card\">\n <svg class=\"db-unbalance-card__icon\" viewBox=\"0 0 64 64\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n <rect x=\"12\" y=\"24\" width=\"40\" height=\"16\" rx=\"3\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"4\" y1=\"32\" x2=\"12\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <line x1=\"52\" y1=\"32\" x2=\"60\" y2=\"32\" stroke=\"#1a3c34\" stroke-width=\"2\"\/>\n <circle cx=\"22\" cy=\"22\" r=\"3\" fill=\"#d4622b\"\/>\n <circle cx=\"34\" cy=\"38\" r=\"4\" fill=\"#d4622b\"\/>\n <circle cx=\"46\" cy=\"26\" r=\"2.5\" fill=\"#c49a1a\"\/>\n <\/svg>\n <div class=\"db-unbalance-card__title\">Dynamic<\/div>\n <div class=\"db-unbalance-card__text\">General case: principal inertia axis neither intersects nor parallels rotation axis. The most common real\u2011world pattern. Two\u2011plane correction mandatory.<\/div>\n <\/div>\n<\/div>\n\n<p>In practice, almost every rotor you encounter in the field has dynamic unbalance \u2014 a combination of force and couple components. That is why two\u2011plane balancing is the default procedure for any rotor that is not a thin disc.<\/p>\n\n\n\n<h2 id=\"single-vs-two\">When to Use Single\u2011Plane vs Two\u2011Plane Balancing<\/h2>\n\n<p>The deciding factor is the rotor's <strong>geometry ratio L\/D<\/strong> (axial length to outer diameter) combined with its operating speed.<\/p>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Criterion<\/th>\n <th>Single\u2011Plane (1 sensor)<\/th>\n <th>Two\u2011Plane (2 sensors)<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td><strong>L\/D ratio<\/strong><\/td>\n <td>L\/D < 0.14 (diameter > 7\u00d7 width)<\/td>\n <td>L\/D \u2265 0.14<\/td>\n <\/tr>\n <tr>\n <td><strong>Typical parts<\/strong><\/td>\n <td>Grinding wheel, flywheel, single\u2011disc impeller, pulley, brake disc, saw blade<\/td>\n <td>Fan rotor, mulcher, shaft, roller, multi\u2011stage pump, turbine, crusher<\/td>\n <\/tr>\n <tr>\n <td><strong>Unbalance types corrected<\/strong><\/td>\n <td>Static only (force)<\/td>\n <td>Static + couple + dynamic (force + moment)<\/td>\n <\/tr>\n <tr>\n <td><strong>Correction planes<\/strong><\/td>\n <td>1<\/td>\n <td>2<\/td>\n <\/tr>\n <tr>\n <td><strong>Measurement runs<\/strong><\/td>\n <td>2 (initial + 1 trial)<\/td>\n <td>3 (initial + 2 trials, one per plane)<\/td>\n <\/tr>\n <tr>\n <td><strong>Time on site<\/strong><\/td>\n <td>15\u201320 min<\/td>\n <td>30\u201345 min<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<div class=\"db-note\">\n <div class=\"db-note__title\">Rule of thumb<\/div>\n <div class=\"db-note__text\">If the correction planes are separated by less than \u2153 of the rotor's bearing span, cross\u2011coupling between planes is small and single\u2011plane balancing may work even for L\/D > 0.14. But if you have a two\u2011channel instrument, always use two planes \u2014 it takes only 10 extra minutes and catches couple unbalance that single\u2011plane misses.<\/div>\n<\/div>\n\n\n\n<h2 id=\"iso-grades\">ISO 21940\u201111 Balance Quality Grades<\/h2>\n\n<p>ISO 21940\u201111 (the successor to ISO 1940\u20111) assigns each class of rotating machinery a <strong>balance quality grade G<\/strong>, defined as the maximum permissible velocity of the rotor's centre of gravity in mm\/s. The permissible residual specific unbalance <em>e<sub>per<\/sub><\/em> (in g\u00b7mm\/kg) is derived from the grade and the operating speed:<\/p>\n\n<div class=\"db-formula\">\n <div class=\"db-formula__label\">Permissible specific unbalance<\/div>\n <div class=\"db-formula__expression\">e<sub>per<\/sub> = G \u00d7 1000 \/ \u03c9 = G \u00d7 1000 \/ (2\u03c0 \u00d7 RPM \/ 60)<\/div>\n <div class=\"db-formula__legend\">\n <strong>e<sub>per<\/sub><\/strong> \u2014 permissible residual specific unbalance, g\u00b7mm\/kg<br>\n <strong>G<\/strong> \u2014 balance quality grade (e.g. 6.3 means 6.3 mm\/s)<br>\n <strong>\u03c9<\/strong> \u2014 angular velocity, rad\/s<br>\n <strong>RPM<\/strong> \u2014 operating speed, rev\/min\n <\/div>\n<\/div>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Grade<\/th>\n <th>e\u00b7\u03c9, mm\/s<\/th>\n <th>Machine types<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td><code>G 0.4<\/code><\/td>\n <td>0.4<\/td>\n <td>Gyroscopes, spindles of precision grinding machines<\/td>\n <\/tr>\n <tr>\n <td><code>G 1.0<\/code><\/td>\n <td>1.0<\/td>\n <td>Turbochargers, gas turbines, small electric armatures with special requirements<\/td>\n <\/tr>\n <tr>\n <td><code>G 2.5<\/code><\/td>\n <td>2.5<\/td>\n <td>Electric motors, generators, medium\/large turbines, pumps with special requirements<\/td>\n <\/tr>\n <tr>\n <td><code>G 6.3<\/code><\/td>\n <td>6.3<\/td>\n <td>Fans, pumps, process machinery, flywheels, centrifuges, general industrial machinery<\/td>\n <\/tr>\n <tr>\n <td><code>G 16<\/code><\/td>\n <td>16<\/td>\n <td>Agricultural machinery, crushers, drive shafts (cardan), parts of crushing machines<\/td>\n <\/tr>\n <tr>\n <td><code>G 40<\/code><\/td>\n <td>40<\/td>\n <td>Passenger car wheels, crankshaft assemblies (series production)<\/td>\n <\/tr>\n <tr>\n <td><code>G 100<\/code><\/td>\n <td>100<\/td>\n <td>Crankshaft assemblies of large slow marine diesel engines<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<h3>Worked Example: Fan Rotor<\/h3>\n<p>A centrifugal fan rotor weighs 80 kg, operates at 1,450 RPM, and the correction radius is 250 mm. Required grade: G 6.3.<\/p>\n\n<div class=\"db-formula\">\n <div class=\"db-formula__label\">Calculation<\/div>\n <div class=\"db-formula__expression\">e<sub>per<\/sub> = 6.3 \u00d7 1000 \/ (2\u03c0 \u00d7 1450 \/ 60) = 6300 \/ 151.8 \u2248 41.5 g\u00b7mm\/kg<\/div>\n <div class=\"db-formula__legend\">\n Total permissible unbalance = 41.5 \u00d7 80 = <strong>3,320 g\u00b7mm<\/strong><br>\n At correction radius 250 mm: max residual mass = 3320 \/ 250 = <strong>13.3 g<\/strong> per plane<br>\n That means each correction plane may retain no more than 13.3 g of unbalance \u2014 roughly the weight of three M6 washers.\n <\/div>\n<\/div>\n\n<p>Related standards: <a href=\"https:\/\/vibromera.eu\/glossary\/iso-21940-11\/\">ISO 21940\u201111<\/a> (rigid rotors), <a href=\"https:\/\/vibromera.eu\/glossary\/iso-21940-12\/\">ISO 21940\u201112<\/a> (flexible rotors), <a href=\"https:\/\/vibromera.eu\/glossary\/iso-10816-3-vibration-severity\/\">ISO 10816‑3<\/a> (vibration severity limits), <a href=\"https:\/\/vibromera.eu\/glossary\/iso-1940\/\">ISO 1940<\/a> (legacy predecessor).<\/p>\n\n\n\n<h2 id=\"field-procedure\">Seven\u2011Step Field Balancing Procedure<\/h2>\n\n<p>This is the influence coefficient method for two\u2011plane field balancing, applied with a portable instrument such as the <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\">Balanset\u20111A<\/a>. The same logic works with any two\u2011channel balancing analyser.<\/p>\n\n<div class=\"db-steps\">\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">1<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Prepare the Rotor & Mount Sensors<\/div>\n <div class=\"db-step__text\">\n Clean bearing housings from dirt and grease \u2014 sensors must sit flush on the metal surface. Mount vibration sensor 1 on the bearing housing closest to <strong>Plane 1<\/strong> (usually the drive end). Mount sensor 2 near <strong>Plane 2<\/strong> (non\u2011drive end). Attach reflective tape to the shaft for the laser tachometer. Connect all cables to the measuring unit.\n <\/div>\n\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">2<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Measure Initial Vibration (Run 0)<\/div>\n <div class=\"db-step__text\">\n Start the rotor and bring it to stable operating speed. The instrument measures vibration amplitude (mm\/s) and phase angle (\u00b0) at both sensors simultaneously. This is the <strong>baseline<\/strong> \u2014 the \"sickness\" of the rotor before treatment. Record the values and stop the machine.\n <\/div>\n <div class=\"db-step__tip\">Field tip: Wait at least 10\u201315 seconds after the RPM stabilises before recording. Thermal transients and air currents settle out in the first few seconds.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697405_121.jpg\" alt=\"Initial vibration measurement on a rotor \u2014 Balanset-1A screen showing baseline readings\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">3<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Install Trial Weight in Plane 1 (Run 1)<\/div>\n <div class=\"db-step__text\">\n Stop the rotor. Attach a <strong>trial weight<\/strong> of known mass at an arbitrary angular position in Plane 1. Mark this position clearly \u2014 it becomes your 0\u00b0 reference for angle measurement later. Restart the rotor and record vibration at both sensors. The instrument now knows how the rotor's vibration field changes when mass is added in Plane 1.\n <\/div>\n <div class=\"db-step__tip\">Field tip: Use a bolt with a washer clamped to the rotor rim, or a hose clamp with a nut for quick attachment. The trial weight should produce a measurable vibration change (\u226530 % amplitude change or \u226530\u00b0 phase shift at either sensor).<\/div>\n <div class=\"db-note\" style=\"margin-top:12px;\">\n <div class=\"db-note__icon\">\u2696<\/div>\n <div class=\"db-note__text\"><strong>How much should the trial weight weigh?<\/strong> Use the empirical formula: <code style=\"background:rgba(0,0,0,0.06); padding:2px 6px; border-radius:3px; font-family:'JetBrains Mono',monospace; font-size:13px;\">M<sub>t<\/sub> = M<sub>r<\/sub> \u00d7 K \/ (R<sub>t<\/sub> \u00d7 (N\/100)\u00b2)<\/code> where M<sub>r<\/sub> = rotor mass (g), K = support stiffness coefficient (1\u20135, use 3 for average), R<sub>t<\/sub> = installation radius (cm), N = RPM. Or use our <a href=\"https:\/\/vibromera.eu\/trial-weight-mass-calculator\/\" style=\"color:var(--db-forest); font-weight:600;\">online trial weight calculator<\/a> \u2014 enter your rotor parameters and get the recommended mass instantly.<\/div>\n <\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697404_121.jpg\" alt=\"Installing a calibration weight on the first correction plane\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">4<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Move Trial Weight to Plane 2 (Run 2)<\/div>\n <div class=\"db-step__text\">\n Stop the rotor. Remove the trial weight from Plane 1. Attach the same trial weight (or one of similar known mass) at an arbitrary position in Plane 2. Mark this second reference point. Restart and record vibration at both sensors. Now the instrument has the complete influence coefficient matrix \u2014 four complex coefficients linking unbalance in either plane to vibration at either sensor.\n <\/div>\n <div class=\"db-step__tip\">Field tip: If you use a different trial weight mass in Plane 2, enter the correct value in the software \u2014 the maths adjusts automatically.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697403_121.jpg\" alt=\"Moving the trial weight to the second correction plane for the second trial run\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">5<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Calculate Correction Weights<\/div>\n <div class=\"db-step__text\">\n The instrument solves the influence coefficient equations and displays: <strong>mass (g)<\/strong> and <strong>angle (\u00b0)<\/strong> for Plane 1, and mass (g) and angle (\u00b0) for Plane 2. The angle is measured from the trial weight position in the direction of rotor rotation. If the software indicates \"remove,\" it means the correction weight should go 180\u00b0 opposite the indicated \"add\" position.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">6<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Install Correction Weights<\/div>\n <div class=\"db-step__text\">\n Remove the trial weight from Plane 2. Fabricate or select correction weights matching the calculated masses. Measure the angle from the trial weight reference mark in the direction of rotation. Attach the correction weights firmly \u2014 welding, hose clamps, set\u2011screw weights, or bolts depending on the machine type and speed.\n <\/div>\n <div class=\"db-step__tip\">Field tip: If you cannot place a weight at the exact angle (e.g. only bolt holes available), use the weight\u2011splitting function \u2014 the instrument decomposes the correction vector into two components at the nearest available positions.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10421367.png\" alt=\"Diagram showing correction weight angle measurement \u2014 from trial weight position in direction of rotation\" width=\"447\" height=\"358\">\n <\/div>\n <\/div>\n\n <div class=\"db-step\">\n <div class=\"db-step__number\">7<\/div>\n <div class=\"db-step__body\">\n <div class=\"db-step__title\">Verify Balance (Check Run)<\/div>\n <div class=\"db-step__text\">\n Restart the rotor and record the final vibration. Compare against the initial baseline and against the ISO 21940‑11 tolerance for your machine class. If vibration is within specification, you are done. If not, the instrument can perform a <strong>trim run<\/strong> \u2014 it uses the existing influence coefficients to calculate a small additional correction without new trial weights.\n <\/div>\n <div class=\"db-step__tip\">Field tip: One trim run is usually enough. If you need more than two trims, something has changed between runs \u2014 check for loose weights, thermal growth, or speed variation.<\/div>\n <img loading=\"lazy\" decoding=\"async\" class=\"db-step__img\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/03\/5969837695301697402_121-1024x549.jpg\" alt=\"Final verification run showing significantly reduced vibration levels after balancing\" width=\"750\" height=\"402\">\n <\/div>\n <\/div>\n\n<\/div>\n\n\n<div class=\"db-cta\">\n <div class=\"db-cta__title\">All Seven Steps \u2014 One Instrument<\/div>\n <div class=\"db-cta__text\">The Balanset\u20111A walks you through the entire two\u2011plane procedure on screen. Two accelerometers, laser tachometer, Windows software, and carrying case included.<\/div>\n <div class=\"db-cta__price\">\u20ac1,975<\/div>\n <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\" class=\"db-cta__btn\">View Balanset\u20111A<\/a>\n <a href=\"https:\/\/wa.me\/351927292960\" class=\"db-cta__btn db-cta__btn--whatsapp\" target=\"_blank\" rel=\"noopener\">WhatsApp<\/a>\n<\/div>\n\n\n\n<h2 id=\"trial-weight\">Trial Weight Calculation<\/h2>\n\n<p>The trial weight must be heavy enough to produce a noticeable vibration change, but light enough not to overload bearings or create a dangerous condition. The standard empirical formula accounts for rotor mass, correction radius, operating speed, and support stiffness:<\/p>\n\n<div class=\"db-formula\">\n <div class=\"db-formula__label\">Trial weight mass formula<\/div>\n <div class=\"db-formula__expression\">M<sub>t<\/sub> = M<sub>r<\/sub> \u00d7 K \/ (R<sub>t<\/sub> \u00d7 (N \/ 100)\u00b2)<\/div>\n <div class=\"db-formula__legend\">\n <strong>M<sub>t<\/sub><\/strong> \u2014 trial weight mass, grams<br>\n <strong>M<sub>r<\/sub><\/strong> \u2014 rotor mass, grams<br>\n <strong>K<\/strong> \u2014 support stiffness coefficient (1 = soft mounts, 3 = average, 5 = rigid foundation)<br>\n <strong>R<sub>t<\/sub><\/strong> \u2014 trial weight installation radius, cm<br>\n <strong>N<\/strong> \u2014 operating speed, RPM\n <\/div>\n<\/div>\n\n<p style=\"margin-top:12px;\">Don't want to do the maths by hand? Use our <a href=\"https:\/\/vibromera.eu\/trial-weight-mass-calculator\/\" style=\"color:var(--db-forest); font-weight:600;\">online trial weight calculator \u2197<\/a> \u2014 enter your rotor parameters, support type, and vibration level, and get the recommended mass instantly.<\/p>\n\n<h3>Worked Examples (K = 3, average stiffness)<\/h3>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Machine<\/th>\n <th>Rotor mass<\/th>\n <th>RPM<\/th>\n <th>Radius<\/th>\n <th>Trial weight (K = 3)<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td>Mulcher rotor<\/td>\n <td>120 kg<\/td>\n <td>2,200<\/td>\n <td>30 cm<\/td>\n <td>360,000 \/ (30 \u00d7 484) \u2248 <strong>25 g<\/strong><\/td>\n <\/tr>\n <tr>\n <td>Industrial fan<\/td>\n <td>80 kg<\/td>\n <td>1,450<\/td>\n <td>40 cm<\/td>\n <td>240,000 \/ (40 \u00d7 210.25) \u2248 <strong>29 g<\/strong><\/td>\n <\/tr>\n <tr>\n <td>Centrifuge drum<\/td>\n <td>45 kg<\/td>\n <td>3,000<\/td>\n <td>15 cm<\/td>\n <td>135,000 \/ (15 \u00d7 900) = <strong>10 g<\/strong><\/td>\n <\/tr>\n <tr>\n <td>Crusher shaft<\/td>\n <td>250 kg<\/td>\n <td>900<\/td>\n <td>25 cm<\/td>\n <td>750,000 \/ (25 \u00d7 81) \u2248 <strong>370 g<\/strong><\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<div class=\"db-note\">\n <div class=\"db-note__title\">Practical tip: verify the response<\/div>\n <div class=\"db-note__text\">The formula gives the minimum trial mass that should produce a measurable response. After the trial run, check that the phase shifted by at least 20\u201330\u00b0 and the amplitude changed by 20\u201330%. If the response is too small, double or triple the trial mass and repeat. At very low RPM (< 500), the formula may yield impractically large values \u2014 in that case, use 10% of rotor weight divided by the correction radius as a starting point.<\/div>\n<\/div>\n\n\n\n<h2 id=\"angle-measurement\">Correction Angle Measurement<\/h2>\n\n<p>The balancing instrument outputs two numbers per plane: <strong>mass<\/strong> (how much weight) and <strong>angle<\/strong> (where to place it). The angle is always referenced to the trial weight position.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center; max-width:680px;\">\n <img decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10448629.png\" alt=\"Balanset-1A software \u2014 two-plane balancing result window showing correction weight mass and angle on polar diagram\" width=\"680\" style=\"display:block; margin:0 auto; border-radius:6px; box-shadow:0 2px 12px rgba(0,0,0,0.12);\">\n <figcaption style=\"font-size:13px; color:#666; margin-top:8px;\">Balanset\u20111A result screen: the software calculates correction mass and angle for each plane and displays vectors on a polar chart. Red vectors show the required correction; green shows residual vibration after trim run.<\/figcaption>\n<\/figure>\n\n<h3>How to Measure the Angle<\/h3>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10431396.png\" alt=\"Polar graph showing correction weight angle relative to trial weight position\" width=\"275\" height=\"469\" style=\"display:block; margin:24px auto;\">\n\n<ul class=\"db-inline-list\">\n <li><strong>Reference point (0\u00b0):<\/strong> the angular position where you placed the trial weight. Mark it clearly on the rotor before the trial run.<\/li>\n <li><strong>Measurement direction:<\/strong> always in the direction of rotor rotation.<\/li>\n <li><strong>Reading the angle:<\/strong> the instrument displays angle f\u2081 for Plane 1 and f\u2082 for Plane 2. From the trial weight mark, count that many degrees in the rotation direction \u2014 that is where the correction weight goes.<\/li>\n <li><strong>If removing mass:<\/strong> place the correction at 180\u00b0 opposite the indicated \"add\" position.<\/li>\n<\/ul>\n\n<h3>Weight Splitting to Fixed Positions<\/h3>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10431665.png\" alt=\"Polar graph showing weight split into two fixed bolt-hole positions\" width=\"308\" height=\"514\" style=\"display:block; margin:24px auto;\">\n\n<p>When the rotor has pre\u2011drilled holes or fixed mounting positions (e.g. fan blade bolts), you may not be able to place a weight at the exact calculated angle. The Balanset\u20111A includes a <strong>weight splitting function<\/strong>: you enter the angles of the two nearest available positions, and the software decomposes the single correction vector into two smaller weights at those positions. The combined effect matches the original vector.<\/p>\n\n\n\n<h2 id=\"correction-planes\">Correction Planes & Sensor Placement<\/h2>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/02\/Bs1ManualEngV156-May2023-10485475.png\" alt=\"Diagram showing correction planes and sensor measurement points on a rotor\" width=\"513\" height=\"294\" style=\"display:block; margin:16px auto;\">\n\n<p>The correction plane is the axial position on the rotor where you add or remove mass. The sensor measures vibration at the nearest bearing. A few key rules:<\/p>\n\n<ul class=\"db-inline-list\">\n <li><strong>Sensor goes on the bearing housing<\/strong> \u2014 as close to the bearing centreline as possible, in the radial direction (horizontal preferred).<\/li>\n <li><strong>Plane 1 corresponds to Sensor 1,<\/strong> Plane 2 to Sensor 2. Keep the numbering consistent or the software will swap correction planes.<\/li>\n <li><strong>Maximise plane separation:<\/strong> the further apart the two correction planes, the better the couple resolution. Minimum practical separation is \u2153 of the bearing span.<\/li>\n <li><strong>Choose accessible positions:<\/strong> the correction plane must be a location where you can physically attach weights \u2014 a flange edge, bolt circle, rim, or welding surface.<\/li>\n<\/ul>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/\u0421\u043d\u0438\u043c\u043e\u043a-\u044d\u043a\u0440\u0430\u043d\u0430-\u043e\u0442-2024-05-14-01-28-32-1024x573.png\" alt=\"Mulcher rotor showing correction planes (blue 1 and 2) and weight installation points (red 1 and 2)\" width=\"750\" height=\"420\" style=\"display:block; margin:24px auto;\">\n\n<p>In the photo above, a mulcher rotor is prepared for two\u2011plane balancing. Blue markers 1 and 2 indicate the sensor positions on bearing housings. Red markers 1 and 2 show the correction planes \u2014 in this case, the flanged ends of the rotor body where weights will be welded.<\/p>\n\n<h3>Cantilever (Overhung) Rotor<\/h3>\n\n<p>Cantilever rotors \u2014 fan impellers, flywheels mounted outboard of the bearing span, pump impellers \u2014 require a different sensor and plane layout. Both correction planes are on the same side of the bearings, and sensor placement must account for the overhung mass amplifying couple unbalance.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/2plschcons-1.png\" alt=\"Schematic diagram of sensor connection and correction plane layout for a cantilever (overhung) rotor \u2014 Balanset-1A two-plane setup\" width=\"750\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Sensor connection diagram for a cantilever rotor: both correction planes are outboard of the bearing span.<\/figcaption>\n<\/figure>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/%D0%A1%D0%BD%D0%B8%D0%BC%D0%BE%D0%BA-%D1%8D%D0%BA%D1%80%D0%B0%D0%BD%D0%B0-%D0%BE%D1%82-2024-05-14-01-29-01-1024x659.png\" alt=\"Cantilever rotor balancing in the field \u2014 sensor and correction plane positions marked on actual equipment\" width=\"750\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Field example: cantilever rotor with sensor and correction plane positions marked.<\/figcaption>\n<\/figure>\n\n\n\n<h2 id=\"applications\">Applications by Machine Type<\/h2>\n\n<div class=\"db-app-cards\">\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Industrial Fans & Blowers<\/div>\n <div class=\"db-app-card__specs\">600\u20133,600 RPM \u00b7 G 6.3 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Most common field balancing task. Centrifugal fans, axial fans, blowers. Watch for dust buildup on blades \u2014 it shifts balance over time. Re\u2011balance after cleaning or blade replacement.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Mulcher & Flail Mower Rotors<\/div>\n <div class=\"db-app-card__specs\">1,800\u20132,500 RPM \u00b7 G 16 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Heavy rotors (80\u2013200 kg) with replaceable flails. Unbalance appears after flail wear or replacement. Correct in two planes at the rotor end\u2011flanges. Typical improvement: 12 \u2192 1 mm\/s.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Crushers & Hammer Mills<\/div>\n <div class=\"db-app-card__specs\">600\u20131,200 RPM \u00b7 G 16 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Extremely heavy rotors (200\u20131,000+ kg). Trial weights are large (5\u201315 kg bolts). Low RPM means large permissible unbalance \u2014 but impact loads and bearing cost still justify balancing.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Centrifuges<\/div>\n <div class=\"db-app-card__specs\">1,000\u201310,000 RPM \u00b7 G 2.5\u20136.3 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Basket or disc centrifuges in food, chemical, and pharma. High speed demands tight tolerance. Field balancing avoids lengthy disassembly. Check for product buildup inside drum.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Electric Motors & Generators<\/div>\n <div class=\"db-app-card__specs\">750\u20133,600 RPM \u00b7 G 2.5 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Motor armatures are factory balanced, but re\u2011balancing is needed after winding repair, bearing replacement, or coupling changes. Test with coupling half attached for best results.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Combine Harvester Augers & Rotors<\/div>\n <div class=\"db-app-card__specs\">400\u20131,200 RPM \u00b7 G 16 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Long augers and threshing rotors pick up soil and crop residue imbalance. Seasonal balancing before harvest prevents bearing failure in the field. Correction weights welded to flights.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Pump Impellers<\/div>\n <div class=\"db-app-card__specs\">1,450\u20133,600 RPM \u00b7 G 6.3 \u00b7 Single or Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Overhung impellers often need only single\u2011plane correction if narrow. For multi\u2011stage pumps, each impeller is balanced individually on a mandrel before assembly.<\/div>\n <\/div>\n\n <div class=\"db-app-card\">\n <div class=\"db-app-card__title\">Turbochargers<\/div>\n <div class=\"db-app-card__specs\">30,000\u2013300,000 RPM \u00b7 G 1.0 \u00b7 Two\u2011plane<\/div>\n <div class=\"db-app-card__text\">Ultra\u2011high speed demands G 1.0 or tighter tolerance. Material removal by grinding \u2014 no welded weights at these speeds. Requires high\u2011frequency vibration sensors.<\/div>\n <\/div>\n\n<\/div>\n\n\n\n<h2 id=\"weight-methods\">Weight Attachment Methods<\/h2>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>Method<\/th>\n <th>Attachment<\/th>\n <th>Best for<\/th>\n <th>Limits<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td><strong>Welding<\/strong><\/td>\n <td>Steel washers or plates tack\u2011welded to rotor rim<\/td>\n <td>Mulchers, crushers, heavy industrial rotors<\/td>\n <td>Permanent. Cannot use on aluminium or stainless without special rod<\/td>\n <\/tr>\n <tr>\n <td><strong>Bolts & nuts<\/strong><\/td>\n <td>Bolts through pre\u2011drilled holes with locknuts<\/td>\n <td>Fan impellers, flywheels, coupling flanges<\/td>\n <td>Requires existing holes or new drilling<\/td>\n <\/tr>\n <tr>\n <td><strong>Hose clamps<\/strong><\/td>\n <td>Stainless\u2011steel hose clamp with weight sandwiched<\/td>\n <td>Shafts, rollers, cylindrical rotors in the field<\/td>\n <td>Temporary or semi\u2011permanent. Verify clamp torque<\/td>\n <\/tr>\n <tr>\n <td><strong>Set\u2011screw clip\u2011on<\/strong><\/td>\n <td>Pre\u2011made clip\u2011on weights (like tyre weights)<\/td>\n <td>Fan blades, thin rims, light rotors<\/td>\n <td>Limited mass range. May slip at high RPM<\/td>\n <\/tr>\n <tr>\n <td><strong>Adhesive (epoxy)<\/strong><\/td>\n <td>Weight glued to surface<\/td>\n <td>Precision rotors, clean environments<\/td>\n <td>Requires clean dry surface. Temperature limit ~120\u00b0C<\/td>\n <\/tr>\n <tr>\n <td><strong>Material removal<\/strong><\/td>\n <td>Drilling or grinding material away from heavy side<\/td>\n <td>Turbochargers, high\u2011speed spindles, impellers<\/td>\n <td>Permanent and precise but irreversible. Use when adding weight is not safe<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n\n\n<h2 id=\"common-mistakes\">Common Mistakes in Field Balancing<\/h2>\n\n<div class=\"db-table-wrap\">\n<table class=\"db-table\">\n <thead>\n <tr>\n <th>#<\/th>\n <th>Mistake<\/th>\n <th>Consequence<\/th>\n <th>Fix<\/th>\n <\/tr>\n <\/thead>\n <tbody>\n <tr>\n <td>1<\/td>\n <td><strong>Sensor mounted on a guard or cover<\/strong><\/td>\n <td>Resonance of the cover distorts amplitude and phase readings \u2192 wrong correction<\/td>\n <td>Always mount on the bearing housing metal surface<\/td>\n <\/tr>\n <tr>\n <td>2<\/td>\n <td><strong>Trial weight too light<\/strong><\/td>\n <td>Phase and amplitude change is within noise \u2192 influence coefficients are unreliable<\/td>\n <td>Ensure \u226530% amplitude change or \u226530\u00b0 phase shift at at least one sensor<\/td>\n <\/tr>\n <tr>\n <td>3<\/td>\n <td><strong>Speed variation between runs<\/strong><\/td>\n <td>Vibration at 1\u00d7 changes with RPM\u00b2 \u2014 even 5% speed change corrupts the data<\/td>\n <td>Use a tachometer for precise RPM tracking. Wait for speed to stabilise<\/td>\n <\/tr>\n <tr>\n <td>4<\/td>\n <td><strong>Forgetting to remove the trial weight<\/strong><\/td>\n <td>Correction calculation includes trial weight effect \u2192 result is meaningless<\/td>\n <td>Follow a strict routine: remove trial weight before installing correction weights<\/td>\n <\/tr>\n <tr>\n <td>5<\/td>\n <td><strong>Mixing up Plane 1 and Plane 2<\/strong><\/td>\n <td>Correction weights go in the wrong planes \u2192 vibration increases<\/td>\n <td>Label sensors and planes clearly. Sensor 1 \u2192 Plane 1, Sensor 2 \u2192 Plane 2<\/td>\n <\/tr>\n <tr>\n <td>6<\/td>\n <td><strong>Measuring angle opposite to rotation<\/strong><\/td>\n <td>Correction goes 360\u00b0 \u2212 f instead of f \u2192 opposite side of rotor<\/td>\n <td>Confirm rotation direction before starting. Always measure in rotation direction<\/td>\n <\/tr>\n <tr>\n <td>7<\/td>\n <td><strong>Thermal growth during runs<\/strong><\/td>\n <td>Bearing clearance changes between cold start runs \u2192 drifting measurements<\/td>\n <td>Either warm up to steady state before run 0, or complete all runs quickly (<5 min apart)<\/td>\n <\/tr>\n <tr>\n <td>8<\/td>\n <td><strong>Using single\u2011plane on a long rotor<\/strong><\/td>\n <td>Couple unbalance remains uncorrected \u2192 vibration may even increase at the far bearing<\/td>\n <td>Use two\u2011plane balancing for any rotor where L\/D \u2265 0.14 or plane separation is significant<\/td>\n <\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n\n\n<h2 id=\"field-report\">Field Report: Mulcher Rotor Balancing<\/h2>\n\n<div class=\"db-field-report\">\n <div class=\"db-field-report__badge\">Real field data \u00b7 February 2025<\/div>\n <div class=\"db-field-report__title\">Flail Mulcher \u2014 Maschio Bisonte 280<\/div>\n\n <div class=\"db-field-report__grid\">\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Vibration before<\/div>\n <div class=\"db-field-report__value db-field-report__value--before\">12.4 mm\/s<\/div>\n <\/div>\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Vibration after<\/div>\n <div class=\"db-field-report__value db-field-report__value--after\">0.8 mm\/s<\/div>\n <\/div>\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Reduction<\/div>\n <div class=\"db-field-report__value\" style=\"color:#fff;\">93.5%<\/div>\n <\/div>\n <div class=\"db-field-report__stat\">\n <div class=\"db-field-report__label\">Time on site<\/div>\n <div class=\"db-field-report__value\" style=\"color:#fff;\">38 min<\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-field-report__detail\">\n <p><strong>Machine:<\/strong> Maschio Bisonte 280 flail mulcher, 165 kg rotor, 2,100 RPM PTO speed. Client reported severe vibration after replacing 8 flails.<\/p>\n <p><strong>Setup:<\/strong> Two accelerometers on bearing housings, laser tachometer on PTO shaft. Balanset-1A two-plane mode.<\/p>\n <p><strong>Run 0:<\/strong> Sensor 1 = 12.4 mm\/s @ 47\u00b0, Sensor 2 = 8.9 mm\/s @ 213\u00b0. ISO 10816-3 zone D (danger).<\/p>\n <p><strong>Trial runs:<\/strong> 500 g trial weight used in both planes. Clear response \u2014 amplitude change >60% at both sensors.<\/p>\n <p><strong>Correction:<\/strong> Plane 1: 340 g welded at 128\u00b0. Plane 2: 215 g welded at 276\u00b0.<\/p>\n <p><strong>Verification:<\/strong> Sensor 1 = 0.8 mm\/s, Sensor 2 = 0.6 mm\/s. ISO zone A (good). No trim run needed.<\/p>\n <\/div>\n<\/div>\n\n\n\n<h2 id=\"fan-balancing\">Two\u2011Plane Dynamic Balancing of a Fan<\/h2>\n\n<p>Industrial fans \u2014 centrifugal, axial, and mixed\u2011flow \u2014 are among the most common rotors balanced in the field. The procedure below walks through a real two\u2011plane job on a radial fan using the Balanset\u20111A.<\/p>\n\n<h3>Determining Planes and Installing Sensors<\/h3>\n\n<p>Clean the surfaces for sensor installation from dirt and oil. Sensors must fit snugly to the metal surface of the bearing housing \u2014 never mount on covers, guards, or unsupported sheet\u2011metal panels.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/2plschcons-1.png\" alt=\"Sensor connection diagram for fan two-plane balancing \u2014 Balanset-1A setup with correction planes marked\" width=\"536\" height=\"283\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Sensor connection and correction plane layout for a cantilever\u2011mounted fan impeller.<\/figcaption>\n<\/figure>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/%D0%A1%D0%BD%D0%B8%D0%BC%D0%BE%D0%BA-%D1%8D%D0%BA%D1%80%D0%B0%D0%BD%D0%B0-%D0%BE%D1%82-2024-05-14-01-29-01-1024x659.png\" alt=\"Fan rotor with sensor positions and correction planes marked in red and green zones\" width=\"750\" height=\"483\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Sensor and correction plane positions on a fan rotor: Sensor 1 (red) near front, Sensor 2 (green) near rear.<\/figcaption>\n<\/figure>\n\n<ul class=\"db-inline-list\">\n <li><strong>Sensor 1 (red):<\/strong> Install closer to the front of the fan (Plane 1 side).<\/li>\n <li><strong>Sensor 2 (green):<\/strong> Install closer to the rear of the fan (Plane 2 side).<\/li>\n <li><strong>Plane 1 (red zone):<\/strong> Correction plane on the impeller disc, closer to the front.<\/li>\n <li><strong>Plane 2 (green zone):<\/strong> Correction plane closer to the back plate or hub.<\/li>\n<\/ul>\n\n<p>Connect both vibration sensors and the laser tachometer to the Balanset\u20111A. Attach reflective tape to the shaft or hub for RPM reference.<\/p>\n\n<h3>Balancing Process<\/h3>\n\n<p>Start the fan and take initial vibration measurements (Run 0). Install a trial weight of known mass on Plane 1 at an arbitrary point, run the fan, and record the vibration change (Run 1). Move the trial weight to Plane 2 at an arbitrary point, run the fan again, and record (Run 2). The Balanset\u20111A software uses all three measurements to calculate the correction mass and angle for each plane.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/5384253216985827502_120.jpg\" alt=\"Installing correction weights on a fan impeller after two-plane balancing with Balanset-1A\" width=\"622\" height=\"395\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Correction weights installed on the fan impeller at positions calculated by the Balanset\u20111A.<\/figcaption>\n<\/figure>\n\n<h3>Angle Measurement for Fan Correction Weights<\/h3>\n\n<p>The angle is measured from the trial weight position in the direction of fan rotation \u2014 exactly as described in the <a href=\"#angle-measurement\">Correction Angle Measurement<\/a> section above. Mark where the trial weight was placed (0\u00b0 reference), then count the indicated angle along the rotation direction to find the correction weight position.<\/p>\n\n<figure style=\"margin:24px auto; text-align:center;\">\n <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2024\/05\/IMG_20190305_162103-1024x589.jpg\" alt=\"Balanset-1A software screen showing two-plane balancing results for a fan \u2014 polar diagram with correction vectors\" width=\"750\" height=\"431\" style=\"display:block; margin:0 auto;\">\n <figcaption style=\"font-size:13px; color:#888; margin-top:6px;\">Balanset\u20111A two\u2011plane balancing result screen: correction mass and angle displayed for both planes.<\/figcaption>\n<\/figure>\n\n<p>Based on the angles and masses calculated by the software, install the correction weights on Plane 1 and Plane 2. Run the fan once more and verify that vibration has dropped to an acceptable level per <a href=\"#iso-grades\">ISO 21940\u201111<\/a> (typically G 6.3 for general\u2011purpose fans). If residual vibration is still above target, perform one trim run.<\/p>\n\n\n\n<h2 id=\"faq\">Frequently Asked Questions<\/h2>\n\n<div class=\"db-faq\">\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n What is the difference between static and dynamic balancing?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Static balancing corrects unbalance in a single plane \u2014 the rotor's centre of gravity is shifted back to the rotation axis. It works for narrow, disc-shaped parts where diameter is greater than 7 times the width. Dynamic balancing corrects unbalance in two planes simultaneously, addressing both force and couple unbalance. It is required for any elongated rotor where masses are distributed along the shaft length. A rotor can be statically balanced yet dynamically unbalanced \u2014 the couple component is invisible until the rotor spins.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n How do I calculate the trial weight mass for field balancing?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Use the formula: M<sub>t<\/sub> = M<sub>r<\/sub> \u00d7 K \/ (R<sub>t<\/sub> \u00d7 (N\/100)\u00b2), where M is in grams, R in cm, and N in RPM. K is the support stiffness coefficient (1 = soft, 3 = average, 5 = rigid). The goal is to produce at least 20\u201330% amplitude change or 20\u201330\u00b0 phase shift. Or skip the maths and use our <a href=\"https:\/\/vibromera.eu\/trial-weight-mass-calculator\/\" style=\"color:var(--db-forest); font-weight:600;\">online trial weight calculator<\/a>. At low speeds below 500 RPM, use the 10% static rule instead: trial mass = 10% of rotor mass \/ correction radius.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n When should I use single-plane vs two-plane balancing?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Use single-plane for narrow disc-shaped rotors where diameter exceeds 7 times the axial width \u2014 flywheels, grinding wheels, saw blades. Use two-plane for anything longer: shafts, fan impellers, mulcher rotors, rollers, multi-stage pump assemblies. When in doubt, always choose two-plane \u2014 it catches couple unbalance that single-plane misses, and only adds one extra measurement run (about 10 minutes).\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n What ISO standard covers rotor balancing tolerances?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n ISO 21940-11:2016 is the current standard for rigid rotors. It replaced ISO 1940-1:2003. It defines balance quality grades from G 0.4 (gyroscopes) to G 4000 (slow marine diesel crankshafts). Common grades: G 6.3 for fans and pumps, G 2.5 for electric motors, G 1.0 for turbocharger rotors, G 16 for agricultural machinery and crushers. The grade times the angular velocity gives the maximum permissible CG velocity in mm\/s \u2014 from there you calculate the allowable residual mass at the correction radius.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n How do I measure the angle for correction weight placement?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n The instrument calculates the correction angle relative to the trial weight position. Mark where you placed the trial weight \u2014 this is your 0\u00b0 reference. Then measure the indicated angle in the direction of rotor rotation from that reference point. The correction weight goes at the resulting position. If the instrument says to remove weight, place it 180\u00b0 opposite. Use a protractor or divide the circumference into marked segments before starting.\n <\/div>\n <\/div>\n <\/div>\n\n <div class=\"db-faq__item\">\n <button class=\"db-faq__question\" onclick=\"this.parentElement.classList.toggle('open')\">\n Can I balance a rotor without removing it from the machine?\n <\/button>\n <div class=\"db-faq__answer\">\n <div class=\"db-faq__answer-inner\">\n Yes \u2014 this is called field balancing or in-situ balancing. You mount vibration sensors on the bearing housings, attach a tachometer reference, and run the machine at operating speed. A portable instrument like the Balanset-1A guides you through the trial weight sequence and calculates corrections. Field balancing saves hours of disassembly time, eliminates alignment errors from reinstallation, and balances the rotor under real operating conditions \u2014 including the effect of coupling, thermal growth, and actual bearing stiffness.\n <\/div>\n <\/div>\n <\/div>\n\n<\/div>\n\n\n\n<h2 id=\"equipment\">Equipment for Field Balancing<\/h2>\n\n<p>The <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\">Balanset\u20111A<\/a> is a two\u2011channel portable instrument that handles single\u2011plane and two\u2011plane dynamic balancing, plus vibration analysis (overall velocity, spectra, waveform). It ships as a complete kit:<\/p>\n\n<ul class=\"db-inline-list\">\n <li>2\u00d7 piezoelectric vibration sensors with magnetic mounts<\/li>\n <li>Laser tachometer (non\u2011contact RPM sensor) with reflective tape<\/li>\n <li>USB measuring unit (connects to any Windows laptop)<\/li>\n <li>Software: balancing wizard, vibration meter, spectrum analyser<\/li>\n <li>Carrying case with all cables and accessories<\/li>\n<\/ul>\n\n<p>RPM range: 300\u2013100,000. Vibration range: 0.5\u201380 mm\/s RMS. Phase accuracy: \u00b11\u00b0. Weight splitting, trim runs, tolerance checking, and report generation included in the software. Full kit weighs 3.5 kg.<\/p>\n\n<div class=\"db-cta\">\n <div class=\"db-cta__title\">Balanset\u20111A \u2014 Portable Balancer & Vibration Analyser<\/div>\n <div class=\"db-cta__text\">Two channels. Two planes. One instrument for field balancing, vibration measurement, and ISO tolerance verification.<\/div>\n <div class=\"db-cta__price\">\u20ac1,975<\/div>\n <a href=\"https:\/\/vibromera.eu\/product\/balanset-1\/\" class=\"db-cta__btn\">Order Now<\/a>\n <a href=\"https:\/\/wa.me\/351927292960\" class=\"db-cta__btn db-cta__btn--whatsapp\" target=\"_blank\" rel=\"noopener\">Ask via WhatsApp<\/a>\n<\/div>\n\n<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.jpg\" alt=\"Balanset-1A portable balancer and vibration analyzer \u2014 complete kit with sensors, tachometer, and carrying case\" width=\"750\" height=\"500\" style=\"display:block; margin:24px auto;\">\n\n\n<div class=\"db-author\">\n <div class=\"db-author__avatar\">NS<\/div>\n <div>\n <div class=\"db-author__name\">Nikolai Shelkovenko<\/div>\n <div class=\"db-author__role\">CEO & Field Engineer \u00b7 Vibromera<\/div>\n <div class=\"db-author__bio\">13+ years in vibration diagnostics and field balancing. Personally balanced 2,000+ rotors across mulchers, fans, crushers, centrifuges, and combine harvesters in 20+ countries.<\/div>\n <\/div>\n<\/div>\n\n\n<div class=\"db-back\">\n <a href=\"https:\/\/vibromera.eu\/knowledge-base\/\">\u2190 Back to Knowledge Base<\/a>\n<\/div>\n\n<\/main>\n<\/div>\n\n<\/div>\n<\/body>\n<\/html><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Dynamic Shaft Balancing Instruction \u2013 ISO 21940 | Vibromera Home \u203a Knowledge Base \u203a Dynamic Shaft Balancing Instruction Field Balancing \u00b7 Complete Guide Dynamic Shaft Balancing Instruction: Static vs Dynamic, Field Procedure & ISO 21940 Grades Everything a field engineer needs to balance rotors on-site \u2014 from the physics of unbalance to […]<\/p>\n","protected":false},"author":2,"featured_media":3695,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ai_generated_summary":"","footnotes":""},"categories":[4,8,10,7,9],"tags":[15,23,20,22],"class_list":["post-4224","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-example","category-crashers","category-impellers","category-mulchers","category-rotors","tag-balancing","tag-field-balancing","tag-impeller","tag-portable-balancer"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts\/4224","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/comments?post=4224"}],"version-history":[{"count":4,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts\/4224\/revisions"}],"predecessor-version":[{"id":101650,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/posts\/4224\/revisions\/101650"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/media\/3695"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/media?parent=4224"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/categories?post=4224"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/tags?post=4224"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}