{"id":100675,"date":"2026-02-28T18:36:26","date_gmt":"2026-02-28T18:36:26","guid":{"rendered":"https:\/\/vibromera.eu\/?p=100675"},"modified":"2026-04-06T09:21:32","modified_gmt":"2026-04-06T09:21:32","slug":"100675","status":"publish","type":"post","link":"https:\/\/vibromera.eu\/bn\/content\/100675\/","title":{"rendered":"\u09a8\u09b0\u09ae \u09aa\u09a6\u099a\u09bf\u09b9\u09cd\u09a8: \u0995\u09be\u09b0\u09a3, \u09a8\u09bf\u09b0\u09cd\u09a3\u09af\u09bc \u098f\u09ac\u0982 \u09b8\u0982\u09b6\u09cb\u09a7\u09a8\u0964"},"content":{"rendered":"
\n\n\n\n\nSoft Foot: Causes, Diagnostics and Correction \u2014 Complete Technical Guide<\/title>\n\n<meta name=\"keywords\" content=\"soft foot, vibration diagnostics, shaft alignment, vibration analysis, cross-phase, Balanset-1A, GOST 20816, ISO 18436, bearings, piping, pumps, misalignment\">\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=DM+Serif+Display:ital@0;1&family=Source+Sans+3:ital,wght@0,300;0,400;0,500;0,600;0,700;1,400;1,500&family=JetBrains+Mono:wght@400;500&display=swap\" rel=\"stylesheet\">\n<style>\n:root {\n --bg: #f5f2ed;\n --bg-warm: #ece8e1;\n --card: #ffffff;\n --card-alt: #faf8f5;\n --border: #d9d3c7;\n --border-light: #e8e3da;\n --accent: #2d5a27;\n --accent-light: #3d7a35;\n --accent-bg: #e8f0e6;\n --accent-bg2: rgba(45,90,39,0.06);\n --secondary: #8b6914;\n --secondary-light: #b8922e;\n --secondary-bg: #fdf6e3;\n --text: #2c2a26;\n --text-body: #3d3b36;\n --text-muted: #7a756b;\n --text-light: #9e9889;\n --heading: #1a1815;\n --red: #b8372b;\n --red-bg: #fdf0ee;\n --blue: #2a5a8c;\n --blue-bg: #eef4fa;\n --green: #2d6b30;\n --green-bg: #edf5ed;\n --warn: #9a6b12;\n --warn-bg: #fef9ec;\n --table-head: #f0ece5;\n --table-stripe: #faf8f5;\n --shadow-sm: 0 1px 3px rgba(44,42,38,0.06);\n --shadow-md: 0 4px 16px rgba(44,42,38,0.08);\n --shadow-lg: 0 8px 32px rgba(44,42,38,0.10);\n --radius: 12px;\n --radius-sm: 8px;\n --radius-lg: 16px;\n}\n\n*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }\nhtml { scroll-behavior: smooth; }\n\nbody {\n font-family: 'Source Sans 3', Georgia, serif;\n background: var(--bg);\n color: var(--text-body);\n line-height: 1.8;\n font-size: 18px;\n -webkit-font-smoothing: antialiased;\n -moz-osx-font-smoothing: grayscale;\n}\n\n\/* \u2500\u2500 LAYOUT \u2500\u2500 *\/\n.page-wrapper {\n max-width: 1400px;\n margin: 0 auto;\n display: grid;\n grid-template-columns: 280px 1fr;\n gap: 0;\n min-height: 100vh;\n}\n\n\/* \u2500\u2500 SIDEBAR \/ TOC \u2500\u2500 *\/\n.sidebar {\n position: sticky;\n top: 0;\n height: 100vh;\n overflow-y: auto;\n background: var(--card);\n border-right: 1px solid var(--border-light);\n padding: 40px 24px 40px 32px;\n scrollbar-width: thin;\n scrollbar-color: var(--border) transparent;\n}\n.sidebar::-webkit-scrollbar { width: 4px; }\n.sidebar::-webkit-scrollbar-track { background: transparent; }\n.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }\n\n.sidebar-logo {\n font-family: 'DM Serif Display', Georgia, serif;\n font-size: 20px;\n color: var(--accent);\n margin-bottom: 8px;\n letter-spacing: -0.3px;\n}\n.sidebar-subtitle {\n font-size: 12px;\n color: var(--text-light);\n text-transform: uppercase;\n letter-spacing: 1.5px;\n font-weight: 600;\n margin-bottom: 32px;\n padding-bottom: 20px;\n border-bottom: 1px solid var(--border-light);\n}\n\n.toc-title {\n font-size: 11px;\n font-weight: 700;\n text-transform: uppercase;\n letter-spacing: 2px;\n color: var(--text-light);\n margin-bottom: 16px;\n}\n\n.toc-list {\n list-style: none;\n margin: 0;\n padding: 0;\n}\n.toc-list li {\n margin-bottom: 2px;\n}\n.toc-list a {\n display: block;\n font-size: 14px;\n color: var(--text-muted);\n text-decoration: none;\n padding: 6px 12px;\n border-radius: 6px;\n line-height: 1.45;\n transition: all 0.2s ease;\n border-left: 2px solid transparent;\n}\n.toc-list a:hover {\n color: var(--accent);\n background: var(--accent-bg2);\n border-left-color: var(--accent);\n}\n.toc-list a.active {\n color: var(--accent);\n background: var(--accent-bg);\n font-weight: 600;\n border-left-color: var(--accent);\n}\n.toc-list .toc-sub {\n padding-left: 24px;\n font-size: 13px;\n}\n\n\/* \u2500\u2500 MAIN CONTENT \u2500\u2500 *\/\n.main-content {\n padding: 56px 72px 100px;\n max-width: 1120px;\n}\n\n\/* \u2500\u2500 HERO \u2500\u2500 *\/\n.hero {\n margin-bottom: 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*\/\n.back-to-top {\n position: fixed;\n bottom: 32px;\n right: 32px;\n width: 44px;\n height: 44px;\n background: var(--accent);\n color: #fff;\n border: none;\n border-radius: 50%;\n cursor: pointer;\n display: flex;\n align-items: center;\n justify-content: center;\n box-shadow: var(--shadow-md);\n opacity: 0;\n transition: opacity 0.3s ease, transform 0.2s ease;\n z-index: 100;\n}\n.back-to-top.visible { opacity: 1; }\n.back-to-top:hover { transform: scale(1.1); }\n\n\/* \u2500\u2500 READING PROGRESS \u2500\u2500 *\/\n.progress-bar {\n position: fixed;\n top: 0;\n left: 0;\n height: 3px;\n background: var(--accent);\n z-index: 999;\n transition: width 0.1s linear;\n}\n\n\/* \u2500\u2500 RESPONSIVE \u2500\u2500 *\/\n@media (max-width: 900px) {\n .page-wrapper {\n grid-template-columns: 1fr;\n }\n .sidebar {\n position: relative;\n height: auto;\n border-right: none;\n border-bottom: 1px solid var(--border-light);\n padding: 24px;\n }\n .main-content {\n padding: 32px 20px 60px;\n }\n .hero h1 { font-size: 32px; }\n h2 { font-size: 26px; }\n .type-cards { grid-template-columns: 1fr; }\n .spec-grid { grid-template-columns: 1fr; }\n .stat-row { grid-template-columns: repeat(2, 1fr); }\n .workflow-strip { flex-direction: column; }\n .workflow-step:not(:last-child)::after { display: none; }\n .workflow-step { border-radius: var(--radius-sm) !important; margin-bottom: 8px; }\n}\n<\/style>\n<\/head>\n<body>\n\n<!-- Reading progress bar -->\n<div class=\"progress-bar\" id=\"progressBar\" style=\"width:0%\"><\/div>\n\n<!-- Back to top button -->\n<button class=\"back-to-top\" id=\"backToTop\" onclick=\"window.scrollTo({top:0,behavior:'smooth'})\">\n <svg width=\"20\" height=\"20\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2.5\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polyline points=\"18 15 12 9 6 15\"\/><\/svg>\n<\/button>\n\n<div class=\"page-wrapper\">\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 SIDEBAR \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<aside class=\"sidebar\">\n <div class=\"sidebar-logo\">VibroMera<\/div>\n <div class=\"sidebar-subtitle\">Technical Knowledge Base<\/div>\n\n <div class=\"toc-title\">Table of Contents<\/div>\n <ul class=\"toc-list\">\n <li><a href=\"#definition\" data-section=\"definition\">1. Definition & Physical Nature<\/a><\/li>\n <li><a href=\"#classification\" data-section=\"classification\">2. Soft Foot Classification<\/a><\/li>\n <li><a href=\"#impact\" data-section=\"impact\">3. Impact on Vibration Condition<\/a><\/li>\n <li><a href=\"#diagnostics\" data-section=\"diagnostics\">4. Diagnostic Methods<\/a><\/li>\n <li><a href=\"#static\" data-section=\"static\" class=\"toc-sub\">4.1 Static Detection<\/a><\/li>\n <li><a href=\"#dynamic\" data-section=\"dynamic\" class=\"toc-sub\">4.2 Dynamic Detection<\/a><\/li>\n <li><a href=\"#cross-phase\" data-section=\"cross-phase\" class=\"toc-sub\">4.3 Cross-Phase Analysis<\/a><\/li>\n <li><a href=\"#piping\" data-section=\"piping\">5. Pipe-Induced Soft Foot<\/a><\/li>\n <li><a href=\"#contact-area\" data-section=\"contact-area\">6. Contact Area Requirements<\/a><\/li>\n <li><a href=\"#correction\" data-section=\"correction\">7. Correction Procedure<\/a><\/li>\n <li><a href=\"#instrumentation\" data-section=\"instrumentation\">8. Instrumentation<\/a><\/li>\n <li><a href=\"#standards\" data-section=\"standards\">9. Normative References<\/a><\/li>\n <li><a href=\"#conclusion\" data-section=\"conclusion\">10. Conclusion<\/a><\/li>\n <\/ul>\n<\/aside>\n\n<!-- \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 MAIN \u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550\u2550 -->\n<main class=\"main-content\">\n\n<!-- HERO -->\n<header class=\"hero\">\n <span class=\"hero-badge\">Vibration Diagnostics<\/span>\n <h1>Soft Foot: Causes, Diagnostics and Correction<\/h1>\n <p class=\"hero-intro\"><strong>Soft foot<\/strong> is one of the most common yet underestimated causes of excessive vibration in rotating equipment. According to field service statistics, <strong>up to 80%<\/strong> of machines at industrial plants operate with uncorrected soft foot. This article provides a detailed look at the physics of the phenomenon, its classification, detection methods \u2014 from feeler gauges to cross-phase vibration analysis \u2014 and practical correction techniques.<\/p>\n <div class=\"hero-meta\">\n <span class=\"hero-meta-item\">\n <svg viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M12 8v4l3 3\"\/><circle cx=\"12\" cy=\"12\" r=\"10\"\/><\/svg>\n 15 min read\n <\/span>\n <span class=\"hero-meta-item\">\n <svg viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M4 19.5A2.5 2.5 0 0 1 6.5 17H20\"\/><path d=\"M6.5 2H20v20H6.5A2.5 2.5 0 0 1 4 19.5v-15A2.5 2.5 0 0 1 6.5 2z\"\/><\/svg>\n ISO 20816 \u00b7 ISO 18436 \u00b7 ISO 1940\n <\/span>\n <span class=\"hero-meta-item\">\n <svg viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M20 7h-9\"\/><path d=\"M14 17H5\"\/><circle cx=\"17\" cy=\"17\" r=\"3\"\/><circle cx=\"7\" cy=\"7\" r=\"3\"\/><\/svg>\n Balanset-1A\n <\/span>\n <\/div>\n<\/header>\n\n<!-- \u2550\u2550\u2550 SECTION 1 \u2550\u2550\u2550 -->\n<h2 id=\"definition\"><span class=\"section-num\">1.<\/span> Definition and Physical Nature<\/h2>\n\n<p><strong>Soft foot<\/strong> is a condition in which one or more machine feet do not have full contact with the foundation frame (sole plate, baseplate) before the hold-down bolts are tightened. When such a bolt is tightened, the machine casing deforms, the bearing bore geometry is distorted, and the rotor axis deviates from its designed position.<\/p>\n\n<p>Physically, the following occurs: the tightening force of a bolt on a foot with incomplete contact creates a bending moment in the casing. This deformation is transmitted to the bearing supports, causing:<\/p>\n\n<ul>\n <li>Misalignment of rolling bearing inner rings<\/li>\n <li>Uneven load distribution in plain bearings<\/li>\n <li>Angular misalignment of coupled machine shafts<\/li>\n <li>Dynamic unbalance due to rotor deflection<\/li>\n<\/ul>\n\n<p>As a result, vibration increases at the rotational frequency (1\u00d7), and in severe cases, at harmonic multiples as well.<\/p>\n\n<div class=\"key-fact\">\n <div class=\"key-fact-label\">Field Data<\/div>\n <p>There are documented cases where correcting soft foot on a <strong>single bolt<\/strong> reduced the vibration velocity (RMS) from <strong>12 mm\/s to 2 mm\/s<\/strong> \u2014 a sixfold reduction.<\/p>\n<\/div>\n\n<!-- \u2550\u2550\u2550 SECTION 2 \u2550\u2550\u2550 -->\n<h2 id=\"classification\"><span class=\"section-num\">2.<\/span> Soft Foot Classification<\/h2>\n\n<p>International practice distinguishes four types of soft foot. Each requires a different approach to identification and correction.<\/p>\n\n<div class=\"type-cards\">\n <div class=\"type-card\">\n <div class=\"type-card-num\">1<\/div>\n <h4>Parallel (Air-Gap) Soft Foot<\/h4>\n <p>A uniform air gap is present under the foot across the entire bearing surface. Causes include: a short foot, non-flatness of the sole plate, or incorrect shim thickness.<\/p>\n <span class=\"correction\">\u2713 Flat calibrated shims<\/span>\n <\/div>\n <div class=\"type-card\">\n <div class=\"type-card-num\">2<\/div>\n <h4>Angular Soft Foot<\/h4>\n <p>The foot contacts the frame along only one edge or corner. When the bolt is tightened, the opposite side lifts, distorting the casing. Occurs when the foot is not perpendicular to the bolt axis or when the surface has wedge-shaped wear.<\/p>\n <span class=\"correction\">\u2713 Tapered \/ stepped shims<\/span>\n <\/div>\n <div class=\"type-card\">\n <div class=\"type-card-num\">3<\/div>\n <h4>Squishy (Springy) Soft Foot<\/h4>\n <p>The surface formally contacts the frame, but compressible material is present: excessive thin shims, paint, dirt, corrosion, or gasket residue. Alignment \"drifts\" over time as it settles. Identified by unstable repeated measurements.<\/p>\n <span class=\"correction\">\u2713 Clean surfaces, \u22643 shims<\/span>\n <\/div>\n <div class=\"type-card\">\n <div class=\"type-card-num\">4<\/div>\n <h4>Induced Soft Foot<\/h4>\n <p>The foot and frame have correct geometry, but external forces \u2014 pipe strain, cable tray loads, guard forces, jacking bolt pressure \u2014 pull the casing out of the support plane. Most insidious: static measurements may not reveal it.<\/p>\n <span class=\"correction\">\u2713 Pipe strain correction<\/span>\n <\/div>\n<\/div>\n\n<!-- SVG: Soft foot types cross-section -->\n<div class=\"infographic\">\n <div class=\"infographic-title\">Soft Foot Classification \u2014 Cross-Section Diagram<\/div>\n <svg viewBox=\"0 0 840 220\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"max-width:820px;\" role=\"img\" aria-labelledby=\"svg-softfoot-types-title2\" aria-describedby=\"svg-softfoot-types-desc2\">\n <title id=\"svg-softfoot-types-title2\">Soft Foot Classification: parallel, angular, squishy and induced<\/title>\n <desc id=\"svg-softfoot-types-desc2\">Diagram showing four types of soft foot in cross-section.<\/desc>\n <rect x=\"0\" y=\"0\" width=\"840\" height=\"220\" rx=\"12\" fill=\"#faf8f5\"\/>\n\n <!-- 1. Parallel -->\n <g transform=\"translate(20,14)\">\n <text x=\"90\" y=\"16\" fill=\"#2d5a27\" font-size=\"13\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">1 \u00b7 Parallel<\/text>\n <rect x=\"20\" y=\"110\" width=\"140\" height=\"20\" rx=\"3\" fill=\"#e8e3da\" stroke=\"#b8a88a\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"124\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FRAME<\/text>\n <rect x=\"35\" y=\"90\" width=\"110\" height=\"16\" rx=\"2\" fill=\"none\" stroke=\"#9a6b12\" stroke-width=\"1.5\" stroke-dasharray=\"5,3\"\/>\n <text x=\"90\" y=\"102\" fill=\"#9a6b12\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">gap<\/text>\n <rect x=\"30\" y=\"60\" width=\"120\" height=\"28\" rx=\"3\" fill=\"#d9d3c7\" stroke=\"#8b6914\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"78\" fill=\"#3d3b36\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FOOT<\/text>\n <line x1=\"90\" y1=\"34\" x2=\"90\" y2=\"60\" stroke=\"#7a756b\" stroke-width=\"2\"\/>\n <circle cx=\"90\" cy=\"32\" r=\"4.5\" fill=\"#7a756b\"\/>\n <text x=\"90\" y=\"152\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">Uniform gap<\/text>\n <text x=\"90\" y=\"167\" fill=\"#2d6b30\" font-size=\"10\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u25b8 Flat shims<\/text>\n <\/g>\n\n <!-- 2. Angular -->\n <g transform=\"translate(210,14)\">\n <text x=\"90\" y=\"16\" fill=\"#2d5a27\" font-size=\"13\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">2 \u00b7 Angular<\/text>\n <rect x=\"20\" y=\"110\" width=\"140\" height=\"20\" rx=\"3\" fill=\"#e8e3da\" stroke=\"#b8a88a\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"124\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FRAME<\/text>\n <polygon points=\"30,90 150,74 150,60 30,60\" fill=\"#d9d3c7\" stroke=\"#8b6914\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"77\" fill=\"#3d3b36\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FOOT<\/text>\n <line x1=\"35\" y1=\"91\" x2=\"35\" y2=\"110\" stroke=\"#9a6b12\" stroke-width=\"1.3\" stroke-dasharray=\"4,3\"\/>\n <line x1=\"145\" y1=\"75\" x2=\"145\" y2=\"110\" stroke=\"#9a6b12\" stroke-width=\"1.3\" stroke-dasharray=\"4,3\"\/>\n <text x=\"34\" y=\"106\" fill=\"#9a6b12\" font-size=\"8\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">max<\/text>\n <text x=\"145\" y=\"106\" fill=\"#9a6b12\" font-size=\"8\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">0<\/text>\n <line x1=\"90\" y1=\"34\" x2=\"90\" y2=\"60\" stroke=\"#7a756b\" stroke-width=\"2\"\/>\n <circle cx=\"90\" cy=\"32\" r=\"4.5\" fill=\"#7a756b\"\/>\n <text x=\"90\" y=\"152\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">Wedge gap<\/text>\n <text x=\"90\" y=\"167\" fill=\"#2d6b30\" font-size=\"10\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u25b8 Tapered shims<\/text>\n <\/g>\n\n <!-- 3. Squishy -->\n <g transform=\"translate(410,14)\">\n <text x=\"90\" y=\"16\" fill=\"#2d5a27\" font-size=\"13\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">3 \u00b7 Squishy<\/text>\n <rect x=\"20\" y=\"110\" width=\"140\" height=\"20\" rx=\"3\" fill=\"#e8e3da\" stroke=\"#b8a88a\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"124\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FRAME<\/text>\n <rect x=\"35\" y=\"96\" width=\"110\" height=\"5\" rx=\"1\" fill=\"#e5c77a\" stroke=\"#9a6b12\" stroke-width=\"0.7\"\/>\n <rect x=\"35\" y=\"88\" width=\"110\" height=\"5\" rx=\"1\" fill=\"#e5c77a\" stroke=\"#9a6b12\" stroke-width=\"0.7\"\/>\n <rect x=\"35\" y=\"102\" width=\"110\" height=\"5\" rx=\"1\" fill=\"#e5c77a\" stroke=\"#9a6b12\" stroke-width=\"0.7\"\/>\n <text x=\"158\" y=\"100\" fill=\"#9a6b12\" font-size=\"8\" font-family=\"Source Sans 3,sans-serif\">shims\/dirt<\/text>\n <rect x=\"30\" y=\"60\" width=\"120\" height=\"25\" rx=\"3\" fill=\"#d9d3c7\" stroke=\"#8b6914\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"76\" fill=\"#3d3b36\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FOOT<\/text>\n <line x1=\"90\" y1=\"34\" x2=\"90\" y2=\"60\" stroke=\"#7a756b\" stroke-width=\"2\"\/>\n <circle cx=\"90\" cy=\"32\" r=\"4.5\" fill=\"#7a756b\"\/>\n <text x=\"90\" y=\"152\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">Compressible layer<\/text>\n <text x=\"90\" y=\"167\" fill=\"#2d6b30\" font-size=\"10\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u25b8 Clean, \u22643 shims<\/text>\n <\/g>\n\n <!-- 4. Induced -->\n <g transform=\"translate(610,14)\">\n <text x=\"100\" y=\"16\" fill=\"#2d5a27\" font-size=\"13\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">4 \u00b7 Induced<\/text>\n <rect x=\"20\" y=\"110\" width=\"140\" height=\"20\" rx=\"3\" fill=\"#e8e3da\" stroke=\"#b8a88a\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"124\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FRAME<\/text>\n <rect x=\"30\" y=\"84\" width=\"120\" height=\"24\" rx=\"3\" fill=\"#d9d3c7\" stroke=\"#8b6914\" stroke-width=\"1.2\"\/>\n <text x=\"90\" y=\"100\" fill=\"#3d3b36\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FOOT<\/text>\n <line x1=\"90\" y1=\"54\" x2=\"90\" y2=\"84\" stroke=\"#7a756b\" stroke-width=\"2\"\/>\n <circle cx=\"90\" cy=\"52\" r=\"4.5\" fill=\"#7a756b\"\/>\n <line x1=\"155\" y1=\"70\" x2=\"198\" y2=\"52\" stroke=\"#b8372b\" stroke-width=\"2.5\" marker-end=\"url(#arrowRedL)\"\/>\n <text x=\"192\" y=\"44\" fill=\"#b8372b\" font-size=\"9\" font-family=\"Source Sans 3,sans-serif\">Pipe<\/text>\n <rect x=\"40\" y=\"52\" width=\"100\" height=\"28\" rx=\"4\" fill=\"#e8e3da\" stroke=\"#b8a88a\" stroke-width=\"1\"\/>\n <text x=\"90\" y=\"70\" fill=\"#7a756b\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">CASING<\/text>\n <text x=\"100\" y=\"152\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">External force<\/text>\n <text x=\"100\" y=\"167\" fill=\"#2d6b30\" font-size=\"10\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u25b8 Pipe correction<\/text>\n <\/g>\n <defs>\n <marker id=\"arrowRedL\" markerWidth=\"8\" markerHeight=\"6\" refX=\"7\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#b8372b\"\/><\/marker>\n <\/defs>\n <\/svg>\n <p class=\"infographic-note\"><span class=\"legend-yellow legend-badge\">Gap<\/span><span class=\"legend-red legend-badge\">External force<\/span><span class=\"legend-green legend-badge\">Correction<\/span> First determine the type of soft foot by the nature of the contact, then select the correction method (shims, surface machining, removal of external loads).<\/p>\n<\/div>\n\n\n<!-- \u2550\u2550\u2550 SECTION 3 \u2550\u2550\u2550 -->\n<h2 id=\"impact\"><span class=\"section-num\">3.<\/span> Impact on Machine Vibration Condition<\/h2>\n\n<p>Soft foot has a complex negative effect on machine condition across multiple parameters:<\/p>\n\n<div class=\"table-wrap\">\n<table>\n <thead>\n <tr><th>Parameter<\/th><th>Mechanism of Impact<\/th><\/tr>\n <\/thead>\n <tbody>\n <tr><td><strong>Vibration velocity (RMS, mm\/s)<\/strong><\/td><td>Amplitude increase at 1\u00d7 rotational frequency due to rotor deflection and misalignment<\/td><\/tr>\n <tr><td><strong>Vibration phase<\/strong><\/td><td>Phase angle difference between supports can reach 180\u00b0 \u2014 a characteristic sign of soft foot<\/td><\/tr>\n <tr><td><strong>Spectrum<\/strong><\/td><td>Elevated 1\u00d7 with possible presence of 2\u00d7 and line frequency (for electric motors)<\/td><\/tr>\n <tr><td><strong>Bearing life<\/strong><\/td><td>Ring misalignment causes point overload on rolling elements, drastically reducing service life<\/td><\/tr>\n <tr><td><strong>Shaft alignment<\/strong><\/td><td>Unstable alignment: values \"drift\" from target after bolt tightening<\/td><\/tr>\n <tr><td><strong>Seals<\/strong><\/td><td>Casing deformation disrupts geometry of mechanical seal seats<\/td><\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<div class=\"key-fact\">\n <div class=\"key-fact-label\">Practical Rule<\/div>\n <p>If vibration remains elevated after performing quality shaft alignment, the <strong>first thing to check is soft foot<\/strong>.<\/p>\n<\/div>\n\n\n<!-- \u2550\u2550\u2550 SECTION 4 \u2550\u2550\u2550 -->\n<h2 id=\"diagnostics\"><span class=\"section-num\">4.<\/span> Diagnostic Methods<\/h2>\n\n<h3 id=\"static\">4.1. Static Detection (Feeler Gauges and Dial Indicators)<\/h3>\n\n<p>The most common method during scheduled alignment work.<\/p>\n\n<ol class=\"procedure-list\">\n <li>Loosen all machine hold-down bolts.<\/li>\n <li>Insert a feeler gauge set between each foot and the frame. Record the gaps.<\/li>\n <li>For each foot with a gap exceeding <strong>0.05 mm<\/strong>, select calibrated shims.<\/li>\n <li>Tighten all bolts with a torque wrench.<\/li>\n <li>Repeat the measurement with a dial indicator: mount the base on the frame, position the indicator tip on the foot, and loosen the bolt. Allowable displacement is no more than <strong>0.05 mm (50 \u00b5m)<\/strong>.<\/li>\n<\/ol>\n\n<div class=\"warning-box\">\n <div class=\"warning-box-title\">\n <svg width=\"18\" height=\"18\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M10.29 3.86L1.82 18a2 2 0 001.71 3h16.94a2 2 0 001.71-3L13.71 3.86a2 2 0 00-3.42 0z\"\/><line x1=\"12\" y1=\"9\" x2=\"12\" y2=\"13\"\/><line x1=\"12\" y1=\"17\" x2=\"12.01\" y2=\"17\"\/><\/svg>\n Limitation\n <\/div>\n <p>This method does not detect <strong>induced soft foot<\/strong> that occurs under operating load (temperature, pressure, pipe strain).<\/p>\n<\/div>\n\n<h3 id=\"dynamic\">4.2. Dynamic Detection (Bolt Loosening on a Running Machine)<\/h3>\n\n<p>This method detects soft foot directly under operating conditions \u2014 at temperature, pressure, and pipe strain.<\/p>\n\n<ol class=\"procedure-list\">\n <li>Mount a vibration sensor (accelerometer) on the machine casing near the support.<\/li>\n <li>Connect the instrument in real-time vibration velocity RMS monitoring mode. A portable dual-channel vibrometer such as the <strong>Balanset-1A<\/strong> can be used, enabling simultaneous monitoring of vibration level and phase angle at the rotational frequency.<\/li>\n <li>Sequentially loosen each hold-down bolt (to finger-tight), observing the change in RMS.<\/li>\n <li>Immediately retighten the bolt after checking and move to the next one.<\/li>\n <li>The bolt whose loosening results in a significant reduction in vibration indicates soft foot at that location.<\/li>\n<\/ol>\n\n<div class=\"key-fact\">\n <div class=\"key-fact-label\">Criterion<\/div>\n <p>A reduction in vibration velocity RMS of more than <strong>20%<\/strong> when loosening a single bolt is conclusive evidence of soft foot.<\/p>\n<\/div>\n\n<div class=\"warning-box\">\n <div class=\"warning-box-title\">\n <svg width=\"18\" height=\"18\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M10.29 3.86L1.82 18a2 2 0 001.71 3h16.94a2 2 0 001.71-3L13.71 3.86a2 2 0 00-3.42 0z\"\/><line x1=\"12\" y1=\"9\" x2=\"12\" y2=\"13\"\/><line x1=\"12\" y1=\"17\" x2=\"12.01\" y2=\"17\"\/><\/svg>\n Safety Warning\n <\/div>\n <p>Working with fasteners on running equipment involves elevated risk. Strict compliance with occupational safety requirements is mandatory, including the use of <strong>non-sparking tools<\/strong> in hazardous areas and proper authorization for work on live equipment.<\/p>\n<\/div>\n\n<h3 id=\"cross-phase\">4.3. Cross-Phase Vibration Analysis<\/h3>\n\n<p>The most informative instrumental method, enabling soft foot identification <strong>without loosening fasteners<\/strong> on running equipment.<\/p>\n\n<h4>Required Equipment<\/h4>\n<ul>\n <li>Dual-channel vibration analyzer with cross-phase function<\/li>\n <li>Two accelerometers<\/li>\n <li>Phase reference sensor (tachometer) and a reflective marker on the rotor<\/li>\n<\/ul>\n\n<p>The dual-channel vibrometer <strong>Balanset-1A<\/strong> provides simultaneous measurement of vibration amplitude at 1\u00d7 and the phase angle on two channels with \u00b12\u00b0 accuracy, making it suitable for cross-phase analysis in the field. A photoelectric phase reference sensor (0\u2013360\u00b0 range) is included as standard equipment.<\/p>\n\n<ol class=\"procedure-list\">\n <li>Mount accelerometers on two machine supports in the same direction (e.g., vertical).<\/li>\n <li>Attach the marker to the rotor and aim the tachometer sensor at the marker.<\/li>\n <li>Perform the cross-phase measurement: the instrument determines the vibration phase angle difference between two points at the 1\u00d7 rotational frequency.<\/li>\n<\/ol>\n\n<div class=\"key-fact\">\n <div class=\"key-fact-label\">Diagnostic Criterion<\/div>\n <p>If the phase difference is approximately <strong>180\u00b0<\/strong> with a simultaneously significant amplitude difference between the two supports, this is a characteristic sign of soft foot. The support with the higher amplitude indicates the problem location.<\/p>\n<\/div>\n\n<h4>Differential Diagnostics<\/h4>\n\n<div class=\"table-wrap diff-table-wrap\">\n<table>\n <thead>\n <tr><th>Defect<\/th><th>Phase Difference Between Supports<\/th><th>Amplitude<\/th><\/tr>\n <\/thead>\n <tbody>\n <tr><td><strong>Soft foot<\/strong><\/td><td>\u2248 180\u00b0<\/td><td>Significant difference between supports<\/td><\/tr>\n <tr><td><strong>Unbalance<\/strong><\/td><td>\u2248 0\u00b0 (in-phase)<\/td><td>Comparable levels<\/td><\/tr>\n <tr><td><strong>Misalignment<\/strong><\/td><td>0\u00b0 or 180\u00b0<\/td><td>Depends on misalignment type<\/td><\/tr>\n <\/tbody>\n<\/table>\n<\/div>\n\n<!-- SVG: Cross-phase comparison -->\n<div class=\"infographic\">\n <div class=\"infographic-title\">Cross-Phase Analysis: Unbalance (0\u00b0) vs Soft Foot (180\u00b0)<\/div>\n <svg viewBox=\"0 0 760 300\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"max-width:740px;\" role=\"img\">\n <rect x=\"0\" y=\"0\" width=\"760\" height=\"300\" rx=\"12\" fill=\"#faf8f5\"\/>\n\n <!-- LEFT: In-phase (Unbalance) -->\n <text x=\"190\" y=\"28\" fill=\"#2d6b30\" font-size=\"14\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">Unbalance \u2014 phase \u2248 0\u00b0<\/text>\n <text x=\"190\" y=\"46\" fill=\"#7a756b\" font-size=\"11\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">(in-phase support movement)<\/text>\n\n <text x=\"18\" y=\"96\" fill=\"#2a5a8c\" font-size=\"10\" font-family=\"Source Sans 3,sans-serif\">CH1<\/text>\n <path d=\"M45,90 C65,55 95,55 115,90 C135,125 165,125 185,90 C205,55 235,55 255,90 C275,125 305,125 325,90\" stroke=\"#2a5a8c\" stroke-width=\"2.5\" fill=\"none\"\/>\n <text x=\"18\" y=\"116\" fill=\"#5a8ab8\" font-size=\"10\" font-family=\"Source Sans 3,sans-serif\">CH2<\/text>\n <path d=\"M45,90 C65,60 95,60 115,90 C135,120 165,120 185,90 C205,60 235,60 255,90 C275,120 305,120 325,90\" stroke=\"#5a8ab8\" stroke-width=\"2\" fill=\"none\" stroke-dasharray=\"6,3\"\/>\n <line x1=\"40\" y1=\"90\" x2=\"330\" y2=\"90\" stroke=\"#d9d3c7\" stroke-width=\"1\"\/>\n <text x=\"190\" y=\"150\" fill=\"#2d6b30\" font-size=\"12\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u0394\u03c6 \u2248 0\u00b0<\/text>\n\n <g transform=\"translate(60,165)\">\n <rect x=\"0\" y=\"30\" width=\"240\" height=\"14\" rx=\"2\" fill=\"#e8e3da\"\/>\n <text x=\"120\" y=\"41\" fill=\"#7a756b\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FRAME<\/text>\n <rect x=\"40\" y=\"0\" width=\"160\" height=\"28\" rx=\"4\" fill=\"#d9d3c7\" stroke=\"#b8a88a\" stroke-width=\"1.5\"\/>\n <text x=\"120\" y=\"18\" fill=\"#3d3b36\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">MACHINE<\/text>\n <line x1=\"70\" y1=\"-5\" x2=\"70\" y2=\"-25\" stroke=\"#2d6b30\" stroke-width=\"2\" marker-end=\"url(#arrowG3)\"\/>\n <line x1=\"170\" y1=\"-5\" x2=\"170\" y2=\"-25\" stroke=\"#2d6b30\" stroke-width=\"2\" marker-end=\"url(#arrowG3)\"\/>\n <rect x=\"62\" y=\"-2\" width=\"16\" height=\"6\" rx=\"2\" fill=\"#2a5a8c\"\/>\n <rect x=\"162\" y=\"-2\" width=\"16\" height=\"6\" rx=\"2\" fill=\"#5a8ab8\"\/>\n <\/g>\n\n <line x1=\"380\" y1=\"15\" x2=\"380\" y2=\"285\" stroke=\"#d9d3c7\" stroke-width=\"1.5\" stroke-dasharray=\"6,4\"\/>\n\n <!-- RIGHT: Anti-phase (Soft Foot) -->\n <text x=\"570\" y=\"28\" fill=\"#9a6b12\" font-size=\"14\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">Soft Foot \u2014 phase \u2248 180\u00b0<\/text>\n <text x=\"570\" y=\"46\" fill=\"#7a756b\" font-size=\"11\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">(anti-phase support movement)<\/text>\n\n <text x=\"398\" y=\"96\" fill=\"#2a5a8c\" font-size=\"10\" font-family=\"Source Sans 3,sans-serif\">CH1<\/text>\n <path d=\"M425,90 C445,55 475,55 495,90 C515,125 545,125 565,90 C585,55 615,55 635,90 C655,125 685,125 705,90\" stroke=\"#2a5a8c\" stroke-width=\"2.5\" fill=\"none\"\/>\n <text x=\"398\" y=\"116\" fill=\"#9a6b12\" font-size=\"10\" font-family=\"Source Sans 3,sans-serif\">CH2<\/text>\n <path d=\"M425,90 C445,120 475,120 495,90 C515,60 545,60 565,90 C585,120 615,120 635,90 C655,60 685,60 705,90\" stroke=\"#9a6b12\" stroke-width=\"2\" fill=\"none\" stroke-dasharray=\"6,3\"\/>\n <line x1=\"420\" y1=\"90\" x2=\"710\" y2=\"90\" stroke=\"#d9d3c7\" stroke-width=\"1\"\/>\n <text x=\"570\" y=\"150\" fill=\"#9a6b12\" font-size=\"12\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u0394\u03c6 \u2248 180\u00b0<\/text>\n\n <g transform=\"translate(440,165)\">\n <rect x=\"0\" y=\"30\" width=\"240\" height=\"14\" rx=\"2\" fill=\"#e8e3da\"\/>\n <text x=\"120\" y=\"41\" fill=\"#7a756b\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FRAME<\/text>\n <polygon points=\"40,5 200,0 200,28 40,23\" fill=\"#d9d3c7\" stroke=\"#9a6b12\" stroke-width=\"1.5\"\/>\n <text x=\"120\" y=\"18\" fill=\"#3d3b36\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">MACHINE<\/text>\n <line x1=\"70\" y1=\"-2\" x2=\"70\" y2=\"-22\" stroke=\"#9a6b12\" stroke-width=\"2\" marker-end=\"url(#arrowY3)\"\/>\n <line x1=\"170\" y1=\"0\" x2=\"170\" y2=\"20\" stroke=\"#9a6b12\" stroke-width=\"2\" marker-end=\"url(#arrowYd3)\"\/>\n <rect x=\"155\" y=\"25\" width=\"50\" height=\"7\" rx=\"1\" fill=\"none\" stroke=\"#b8372b\" stroke-width=\"1.2\" stroke-dasharray=\"3,2\"\/>\n <text x=\"210\" y=\"36\" fill=\"#b8372b\" font-size=\"8\" font-weight=\"600\" font-family=\"Source Sans 3,sans-serif\">SF<\/text>\n <rect x=\"62\" y=\"-2\" width=\"16\" height=\"6\" rx=\"2\" fill=\"#2a5a8c\"\/>\n <rect x=\"162\" y=\"-2\" width=\"16\" height=\"6\" rx=\"2\" fill=\"#9a6b12\"\/>\n <\/g>\n\n <defs>\n <marker id=\"arrowG3\" markerWidth=\"8\" markerHeight=\"6\" refX=\"4\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#2d6b30\"\/><\/marker>\n <marker id=\"arrowY3\" markerWidth=\"8\" markerHeight=\"6\" refX=\"4\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#9a6b12\"\/><\/marker>\n <marker id=\"arrowYd3\" markerWidth=\"8\" markerHeight=\"6\" refX=\"4\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#9a6b12\"\/><\/marker>\n <\/defs>\n <\/svg>\n <p class=\"infographic-note\"><span class=\"legend-blue legend-badge\">CH1 \/ CH2<\/span><span class=\"legend-green legend-badge\">\u0394\u03c6 \u2248 0\u00b0<\/span><span class=\"legend-yellow legend-badge\">\u0394\u03c6 \u2248 180\u00b0<\/span> In-phase signals typically indicate unbalance; anti-phase signals point to soft foot. For a definitive conclusion, verify amplitudes, the 1\u00d7\/2\u00d7 spectrum, and the bolt loosening test.<\/p>\n<\/div>\n\n<p>The advantage of the cross-phase method is that it works during normal machine operation and does not require loosening any fasteners.<\/p>\n\n\n<!-- \u2550\u2550\u2550 SECTION 5 \u2550\u2550\u2550 -->\n<h2 id=\"piping\"><span class=\"section-num\">5.<\/span> Pipe-Induced Soft Foot<\/h2>\n\n<p>Pipe strain on pump or compressor equipment is one of the key \u2014 yet most frequently overlooked \u2014 causes of excessive vibration and unstable alignment.<\/p>\n\n<h3>5.1. Mechanism of Occurrence<\/h3>\n\n<p>If piping is connected to a machine flange under strain (without a free fit), the pipe force is constantly applied to the machine casing. Under operating pressure and temperature, this force increases due to thermal expansion. The pipe \"rocks\" the machine, leading to:<\/p>\n\n<ul>\n <li>Periodic changes in shaft alignment<\/li>\n <li>Increased vibration at 1\u00d7 and 2\u00d7 rotational frequency<\/li>\n <li>Premature wear of bearings and mechanical seals<\/li>\n <li>Unstable readings when attempting alignment<\/li>\n<\/ul>\n\n<!-- SVG: Pipe strain -->\n<div class=\"infographic\">\n <div class=\"infographic-title\">Induced Soft Foot: Machine Strain from Piping<\/div>\n <svg viewBox=\"0 0 700 230\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"max-width:680px;\" role=\"img\">\n <rect x=\"0\" y=\"0\" width=\"700\" height=\"230\" rx=\"12\" fill=\"#faf8f5\"\/>\n\n <rect x=\"50\" y=\"160\" width=\"600\" height=\"20\" rx=\"3\" fill=\"#e8e3da\"\/>\n <text x=\"350\" y=\"175\" fill=\"#7a756b\" font-size=\"11\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FOUNDATION<\/text>\n <rect x=\"160\" y=\"140\" width=\"240\" height=\"18\" rx=\"2\" fill=\"#d9d3c7\" stroke=\"#b8a88a\" stroke-width=\"1\"\/>\n <text x=\"280\" y=\"153\" fill=\"#7a756b\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">FRAME<\/text>\n\n <rect x=\"180\" y=\"80\" width=\"200\" height=\"56\" rx=\"6\" fill=\"#e8e3da\" stroke=\"#b8a88a\" stroke-width=\"1.5\"\/>\n <text x=\"280\" y=\"108\" fill=\"#3d3b36\" font-size=\"13\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">PUMP<\/text>\n <text x=\"280\" y=\"124\" fill=\"#7a756b\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">(compressor)<\/text>\n\n <rect x=\"180\" y=\"136\" width=\"20\" height=\"6\" rx=\"1\" fill=\"#d9d3c7\"\/>\n <rect x=\"360\" y=\"136\" width=\"20\" height=\"6\" rx=\"1\" fill=\"#d9d3c7\"\/>\n\n <rect x=\"20\" y=\"88\" width=\"160\" height=\"22\" rx=\"4\" fill=\"#edf5ed\" stroke=\"#2d6b30\" stroke-width=\"1.2\"\/>\n <text x=\"100\" y=\"103\" fill=\"#2d6b30\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">PIPE (suction)<\/text>\n\n <rect x=\"380\" y=\"92\" width=\"290\" height=\"22\" rx=\"4\" fill=\"#fdf0ee\" stroke=\"#b8372b\" stroke-width=\"1.2\"\/>\n <text x=\"525\" y=\"107\" fill=\"#b8372b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">PIPE (discharge) \u2014 under strain!<\/text>\n\n <line x1=\"520\" y1=\"80\" x2=\"400\" y2=\"80\" stroke=\"#b8372b\" stroke-width=\"2.5\" marker-end=\"url(#arrowR4)\"\/>\n <line x1=\"520\" y1=\"125\" x2=\"400\" y2=\"125\" stroke=\"#b8372b\" stroke-width=\"2.5\" marker-end=\"url(#arrowR4)\"\/>\n <text x=\"470\" y=\"72\" fill=\"#b8372b\" font-size=\"10\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">F (strain)<\/text>\n\n <path d=\"M280,78 C300,50 330,50 350,70\" stroke=\"#9a6b12\" stroke-width=\"2\" fill=\"none\" stroke-dasharray=\"5,3\" marker-end=\"url(#arrowY4)\"\/>\n <text x=\"330\" y=\"48\" fill=\"#9a6b12\" font-size=\"10\" font-family=\"Source Sans 3,sans-serif\">deformation<\/text>\n\n <g transform=\"translate(375,82)\">\n <rect x=\"0\" y=\"0\" width=\"6\" height=\"34\" rx=\"1\" fill=\"#9e9889\"\/>\n <rect x=\"-6\" y=\"0\" width=\"6\" height=\"34\" rx=\"1\" fill=\"#9e9889\"\/>\n <text x=\"0\" y=\"46\" fill=\"#9a6b12\" font-size=\"8\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">flange<\/text>\n <\/g>\n\n <g transform=\"translate(480,150)\">\n <circle cx=\"0\" cy=\"0\" r=\"28\" fill=\"none\" stroke=\"#2a5a8c\" stroke-width=\"1\"\/>\n <text x=\"0\" y=\"-32\" fill=\"#2a5a8c\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">4-point check<\/text>\n <text x=\"0\" y=\"-16\" fill=\"#3d3b36\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">12<\/text>\n <text x=\"0\" y=\"20\" fill=\"#3d3b36\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">6<\/text>\n <text x=\"-20\" y=\"4\" fill=\"#3d3b36\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">9<\/text>\n <text x=\"20\" y=\"4\" fill=\"#3d3b36\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">3<\/text>\n <circle cx=\"0\" cy=\"-10\" r=\"2\" fill=\"#9a6b12\"\/>\n <circle cx=\"0\" cy=\"10\" r=\"2\" fill=\"#9a6b12\"\/>\n <circle cx=\"-10\" cy=\"0\" r=\"2\" fill=\"#9a6b12\"\/>\n <circle cx=\"10\" cy=\"0\" r=\"2\" fill=\"#9a6b12\"\/>\n <\/g>\n\n <defs>\n <marker id=\"arrowR4\" markerWidth=\"8\" markerHeight=\"6\" refX=\"7\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#b8372b\"\/><\/marker>\n <marker id=\"arrowY4\" markerWidth=\"8\" markerHeight=\"6\" refX=\"7\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#9a6b12\"\/><\/marker>\n <\/defs>\n <\/svg>\n <p class=\"infographic-note\"><span class=\"legend-red legend-badge\">Strain force<\/span><span class=\"legend-yellow legend-badge\">Deformation<\/span> Red arrows show the pipe strain force that pulls the machine out of its geometry. The 12\u20133\u20136\u20139 circle shows the order for measuring flange gaps at four points before alignment.<\/p>\n<\/div>\n\n<h3>5.2. Piping Condition Inspection<\/h3>\n\n<p>Before shaft alignment, inspection of flange angularity and offset is mandatory.<\/p>\n\n<ol class=\"procedure-list\">\n <li>Disconnect the piping from the machine flange.<\/li>\n <li>Measure the gaps between the pipe flange and machine flange at four points: 12, 3, 6, and 9 o'clock.<\/li>\n <li>Determine the angularity (gap difference at opposite points) and offset (parallel mismatch of flange centerlines).<\/li>\n<\/ol>\n\n<h4>Tolerances<\/h4>\n<ul>\n <li>Ideal angularity and offset value: <strong>0 mm<\/strong><\/li>\n <li>Practically achievable with careful fitting: <strong>0.01\u20130.02 mm<\/strong><\/li>\n <li>Values exceeding <strong>0.05 mm<\/strong> require mandatory correction before alignment<\/li>\n<\/ul>\n\n<h3>5.3. Pipe Fitting<\/h3>\n\n<p>The goal is to achieve a stress-free flange connection without applying external forces. Methods include:<\/p>\n\n<ul>\n <li>Adjusting pipe supports and hangers<\/li>\n <li>Trimming or extending spool pieces<\/li>\n <li>Using expansion joints<\/li>\n <li>Correcting intermediate support positions<\/li>\n<\/ul>\n\n<div class=\"key-fact\">\n <div class=\"key-fact-label\">Industry Reality<\/div>\n <p>According to field practice data, <strong>up to 80% of operating organizations neglect pipe strain verification<\/strong>, continuing to search for the vibration cause elsewhere. This work is labor-intensive, but without it any alignment \u2014 even precision alignment \u2014 will be unstable.<\/p>\n<\/div>\n\n\n<!-- \u2550\u2550\u2550 SECTION 6 \u2550\u2550\u2550 -->\n<h2 id=\"contact-area\"><span class=\"section-num\">6.<\/span> Foot Contact Area Requirements<\/h2>\n\n<p>The minimum contact area of the machine foot with the sole plate (foundation frame) must be <strong>at least 80%<\/strong> of the foot sole area.<\/p>\n\n<p>When the contact area is less than 80%:<\/p>\n\n<ul>\n <li>The load is distributed unevenly, creating local stress concentrations<\/li>\n <li>Shims deform and are indented at point contact zones<\/li>\n <li>Bolt tightening does not provide stable fixation \u2014 alignment \"drifts\" over time<\/li>\n <li>The risk of fatigue failure of the foot or sole plate increases<\/li>\n<\/ul>\n\n<h4>Inspection Methods<\/h4>\n<ul>\n <li><strong>Visual inspection:<\/strong> contact marks, oxidation, scoring on foot and frame surfaces<\/li>\n <li><strong>Prussian Blue (marking paste):<\/strong> apply a thin layer to the sole plate, press the foot down, evaluate the contact pattern<\/li>\n <li><strong>Feeler gauge set:<\/strong> measure around the foot perimeter with the bolt loosened<\/li>\n<\/ul>\n\n<p>If contact is found to be less than 80%, the flatness of the bearing surfaces must be restored: scraping, milling, or grinding of the sole plate and\/or foot sole.<\/p>\n\n\n<!-- \u2550\u2550\u2550 SECTION 7 \u2550\u2550\u2550 -->\n<h2 id=\"correction\"><span class=\"section-num\">7.<\/span> Soft Foot Correction Procedure<\/h2>\n\n<p>Recommended sequence of work when soft foot is detected:<\/p>\n\n<div class=\"steps-flow\">\n <div class=\"step-item\">\n <div class=\"step-num\">1<\/div>\n <div class=\"step-body\">\n <h4>Prepare Bearing Surfaces<\/h4>\n <ul>\n <li>Clean sole plates and foot surfaces of dirt, paint, rust, and old gasket material<\/li>\n <li>Check flatness with a straightedge and feeler gauge set<\/li>\n <li>Machine the surfaces if necessary (grinding, scraping)<\/li>\n <\/ul>\n <\/div>\n <\/div>\n <div class=\"step-item\">\n <div class=\"step-num\">2<\/div>\n <div class=\"step-body\">\n <h4>Verify Contact Area<\/h4>\n <ul>\n <li>Ensure foot-to-sole plate contact is at least 80%<\/li>\n <li>Eliminate any compressible (springy) materials in the contact zone<\/li>\n <\/ul>\n <\/div>\n <\/div>\n <div class=\"step-item\">\n <div class=\"step-num\">3<\/div>\n <div class=\"step-body\">\n <h4>Measure Gaps<\/h4>\n <ul>\n <li>Loosen all hold-down bolts<\/li>\n <li>Measure gaps with feeler gauges or a dial indicator at each foot<\/li>\n <li>Select calibrated stainless steel shims. <strong>No more than 3 shims per foot<\/strong> (to avoid \"squishy\" effect)<\/li>\n <\/ul>\n <\/div>\n <\/div>\n <div class=\"step-item\">\n <div class=\"step-num\">4<\/div>\n <div class=\"step-body\">\n <h4>Check Pipe Strain<\/h4>\n <ul>\n <li>Disconnect the piping<\/li>\n <li>Measure flange angularity and offset at four points<\/li>\n <li>If tolerances are exceeded, correct to achieve a stress-free connection<\/li>\n <\/ul>\n <\/div>\n <\/div>\n <div class=\"step-item\">\n <div class=\"step-num\">5<\/div>\n <div class=\"step-body\">\n <h4>Final Tightening & Verification<\/h4>\n <ul>\n <li>Tighten all bolts with a torque wrench in a cross pattern<\/li>\n <li>Dial indicator check: displacement \u2264 0.05 mm when loosening any bolt<\/li>\n <li>Test run and verify vibration levels<\/li>\n <\/ul>\n <\/div>\n <\/div>\n <div class=\"step-item\">\n <div class=\"step-num\">6<\/div>\n <div class=\"step-body\">\n <h4>Perform Shaft Alignment<\/h4>\n <p>Shaft alignment should be performed <strong>only after soft foot has been fully corrected<\/strong> and piping has been fitted. Otherwise, alignment results will be unstable.<\/p>\n <\/div>\n <\/div>\n<\/div>\n\n\n<!-- \u2550\u2550\u2550 SECTION 8 \u2550\u2550\u2550 -->\n<h2 id=\"instrumentation\"><span class=\"section-num\">8.<\/span> Instrumentation<\/h2>\n\n<h3>8.1. Tools for Static Diagnostics<\/h3>\n<ul>\n <li>Calibrated feeler gauge set (from 0.02 mm)<\/li>\n <li>Dial indicator on a magnetic base (graduation 0.01 mm)<\/li>\n <li>Straightedge<\/li>\n <li>Marking paste (Prussian Blue) for contact area assessment<\/li>\n <li>Calibrated torque wrench<\/li>\n<\/ul>\n\n<h3>8.2. Tools for Dynamic Diagnostics<\/h3>\n\n<p>Dynamic soft foot detection and cross-phase analysis require a portable vibration analyzer with simultaneous dual-channel measurement and phase analysis capabilities.<\/p>\n\n<p>The <strong>Balanset-1A<\/strong> (manufactured by VibroMera) is a portable dual-channel vibrometer-balancer suitable for these tasks. Key specifications relevant to soft foot diagnostics:<\/p>\n\n<div class=\"spec-grid\">\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Vibration Channels<\/span>\n <span class=\"spec-item-value\">2 (simultaneous)<\/span>\n <\/div>\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Speed Range<\/span>\n <span class=\"spec-item-value\">250\u201390,000 RPM<\/span>\n <\/div>\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Vibration Velocity RMS<\/span>\n <span class=\"spec-item-value\">0\u201380 mm\/s<\/span>\n <\/div>\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Phase Accuracy<\/span>\n <span class=\"spec-item-value\">0\u2013360\u00b0, \u00b12\u00b0<\/span>\n <\/div>\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Phase Sensor<\/span>\n <span class=\"spec-item-value\">Photoelectric, included<\/span>\n <\/div>\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Spectral Analysis<\/span>\n <span class=\"spec-item-value\">FFT supported<\/span>\n <\/div>\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Power Supply<\/span>\n <span class=\"spec-item-value\">USB (7\u201320 V)<\/span>\n <\/div>\n <div class=\"spec-item\">\n <span class=\"spec-item-label\">Balancing<\/span>\n <span class=\"spec-item-value\">1 or 2 planes<\/span>\n <\/div>\n<\/div>\n\n<p>The dual-channel architecture of the Balanset-1A enables simultaneous amplitude and phase vibration measurement at two supports, which is a prerequisite for cross-phase soft foot diagnostics. After soft foot correction, the same instrument is used for rotor balancing in its own bearings \u2014 in one or two correction planes \u2014 without equipment disassembly.<\/p>\n\n\n<!-- \u2550\u2550\u2550 SECTION 9 \u2550\u2550\u2550 -->\n<h2 id=\"standards\"><span class=\"section-num\">9.<\/span> Normative References<\/h2>\n\n<ul class=\"standards-list\">\n <li><strong>GOST R ISO 20816-1-2021<\/strong> \u2014 Vibration. Measurement and evaluation of machine vibration. Part 1. General guidelines.<\/li>\n <li><strong>GOST R ISO 18436-2-2005<\/strong> \u2014 Condition monitoring and diagnostics of machines. Vibration condition monitoring and diagnostics. Part 2. Requirements for training and certification of personnel.<\/li>\n <li><strong>ISO 1940-1:2003<\/strong> \u2014 Mechanical vibration. Balance quality requirements for rotors in a constant (rigid) state. Part 1: Specification and verification of balance tolerances.<\/li>\n <li><strong>ISO 10816 \/ ISO 20816<\/strong> \u2014 Series of standards for evaluating machine vibration condition.<\/li>\n<\/ul>\n\n\n<!-- \u2550\u2550\u2550 SECTION 10 \u2550\u2550\u2550 -->\n<h2 id=\"conclusion\"><span class=\"section-num\">10.<\/span> Conclusion<\/h2>\n\n<div class=\"conclusion-box\">\n <h3>Key Takeaway<\/h3>\n <p>Soft foot is a systemic installation defect whose correction is a <strong>mandatory prerequisite<\/strong> for successful shaft alignment and vibration reduction in rotating equipment. Ignoring soft foot renders any subsequent commissioning work pointless: alignment will be unstable, vibration will remain elevated, and bearing and seal service life will be reduced.<\/p>\n<\/div>\n\n<p>Modern portable dual-channel vibrometers such as the <strong>Balanset-1A<\/strong> provide a complete diagnostic cycle \u2014 from soft foot detection via cross-phase analysis to subsequent on-site rotor balancing. Using instrumental diagnostic methods instead of visual inspection greatly increases defect detection reliability and reduces commissioning time.<\/p>\n\n<h4>Recommended Commissioning Workflow<\/h4>\n\n<div class=\"workflow-strip\">\n <div class=\"workflow-step\">\n <div class=\"workflow-step-num\">1<\/div>\n <div class=\"workflow-step-label\">Soft Foot Check & Correction<\/div>\n <\/div>\n <div class=\"workflow-step\">\n <div class=\"workflow-step-num\">2<\/div>\n <div class=\"workflow-step-label\">Pipe Fitting<\/div>\n <\/div>\n <div class=\"workflow-step\">\n <div class=\"workflow-step-num\">3<\/div>\n <div class=\"workflow-step-label\">Shaft Alignment<\/div>\n <\/div>\n <div class=\"workflow-step\">\n <div class=\"workflow-step-num\">4<\/div>\n <div class=\"workflow-step-label\">Rotor Balancing<\/div>\n <\/div>\n <div class=\"workflow-step\">\n <div class=\"workflow-step-num\">5<\/div>\n <div class=\"workflow-step-label\">Final Vibration Check \u2713<\/div>\n <\/div>\n<\/div>\n\n<!-- SVG: Workflow flowchart -->\n<div class=\"infographic\">\n <div class=\"infographic-title\">Rotating Equipment Commissioning Flowchart<\/div>\n <svg viewBox=\"0 0 720 380\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"max-width:700px;\" role=\"img\">\n <rect x=\"0\" y=\"0\" width=\"720\" height=\"380\" rx=\"12\" fill=\"#faf8f5\"\/>\n\n <rect x=\"250\" y=\"15\" width=\"220\" height=\"44\" rx=\"8\" fill=\"#eef4fa\" stroke=\"#2a5a8c\" stroke-width=\"2\"\/>\n <text x=\"360\" y=\"34\" fill=\"#2c2a26\" font-size=\"12\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">1. Soft foot check<\/text>\n <text x=\"360\" y=\"49\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">gauges + indicator + cross-phase<\/text>\n <line x1=\"360\" y1=\"59\" x2=\"360\" y2=\"80\" stroke=\"#2a5a8c\" stroke-width=\"2\" marker-end=\"url(#arrowB2)\"\/>\n\n <polygon points=\"360,80 440,112 360,144 280,112\" fill=\"#fef9ec\" stroke=\"#9a6b12\" stroke-width=\"1.5\"\/>\n <text x=\"360\" y=\"110\" fill=\"#9a6b12\" font-size=\"11\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">SF found?<\/text>\n <text x=\"360\" y=\"124\" fill=\"#9a6b12\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">>0.05 mm<\/text>\n\n <line x1=\"440\" y1=\"112\" x2=\"510\" y2=\"112\" stroke=\"#b8372b\" stroke-width=\"1.5\"\/>\n <text x=\"468\" y=\"106\" fill=\"#b8372b\" font-size=\"10\" font-family=\"Source Sans 3,sans-serif\">Yes<\/text>\n <rect x=\"510\" y=\"92\" width=\"180\" height=\"40\" rx=\"6\" fill=\"#fdf0ee\" stroke=\"#b8372b\" stroke-width=\"1.5\"\/>\n <text x=\"600\" y=\"110\" fill=\"#b8372b\" font-size=\"11\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">Correct SF:<\/text>\n <text x=\"600\" y=\"124\" fill=\"#3d3b36\" font-size=\"9.5\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">shims, cleaning, machining<\/text>\n <path d=\"M600,132 L600,148 L465,148 L465,130 L440,112\" stroke=\"#b8372b\" stroke-width=\"1\" fill=\"none\" stroke-dasharray=\"4,3\" marker-end=\"url(#arrowR5)\"\/>\n\n <line x1=\"360\" y1=\"144\" x2=\"360\" y2=\"168\" stroke=\"#2d6b30\" stroke-width=\"1.5\" marker-end=\"url(#arrowG4)\"\/>\n <text x=\"346\" y=\"160\" fill=\"#2d6b30\" font-size=\"10\" font-family=\"Source Sans 3,sans-serif\">No<\/text>\n\n <rect x=\"250\" y=\"168\" width=\"220\" height=\"44\" rx=\"8\" fill=\"#eef4fa\" stroke=\"#2a5a8c\" stroke-width=\"2\"\/>\n <text x=\"360\" y=\"187\" fill=\"#2c2a26\" font-size=\"12\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">2. Pipe fitting<\/text>\n <text x=\"360\" y=\"202\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">angularity \/ offset \u2264 0.02 mm<\/text>\n <line x1=\"360\" y1=\"212\" x2=\"360\" y2=\"234\" stroke=\"#2a5a8c\" stroke-width=\"2\" marker-end=\"url(#arrowB2)\"\/>\n\n <rect x=\"250\" y=\"234\" width=\"220\" height=\"40\" rx=\"8\" fill=\"#eef4fa\" stroke=\"#2a5a8c\" stroke-width=\"2\"\/>\n <text x=\"360\" y=\"254\" fill=\"#2c2a26\" font-size=\"12\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">3. Shaft alignment<\/text>\n <text x=\"360\" y=\"267\" fill=\"#7a756b\" font-size=\"10\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">laser \/ dial indicator<\/text>\n <line x1=\"360\" y1=\"274\" x2=\"360\" y2=\"296\" stroke=\"#2a5a8c\" stroke-width=\"2\" marker-end=\"url(#arrowB2)\"\/>\n\n <rect x=\"250\" y=\"296\" width=\"220\" height=\"36\" rx=\"8\" fill=\"#eef4fa\" stroke=\"#5a8ab8\" stroke-width=\"1.5\"\/>\n <text x=\"360\" y=\"318\" fill=\"#2c2a26\" font-size=\"12\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">4. Balancing (Balanset-1A)<\/text>\n <line x1=\"360\" y1=\"332\" x2=\"360\" y2=\"348\" stroke=\"#2a5a8c\" stroke-width=\"2\" marker-end=\"url(#arrowB2)\"\/>\n\n <rect x=\"230\" y=\"348\" width=\"260\" height=\"26\" rx=\"13\" fill=\"#edf5ed\" stroke=\"#2d6b30\" stroke-width=\"2\"\/>\n <text x=\"360\" y=\"366\" fill=\"#2d6b30\" font-size=\"12\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">5. Final vibration measurement \u2713<\/text>\n\n <g transform=\"translate(15,20)\">\n <rect x=\"0\" y=\"0\" width=\"200\" height=\"50\" rx=\"6\" fill=\"#faf8f5\" stroke=\"#d9d3c7\" stroke-width=\"1\"\/>\n <text x=\"100\" y=\"18\" fill=\"#2a5a8c\" font-size=\"10\" font-weight=\"600\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">Balanset-1A is used at:<\/text>\n <text x=\"100\" y=\"32\" fill=\"#7a756b\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u25b8 step 1 \u2014 cross-phase<\/text>\n <text x=\"100\" y=\"44\" fill=\"#7a756b\" font-size=\"9\" text-anchor=\"middle\" font-family=\"Source Sans 3,sans-serif\">\u25b8 step 4 \u2014 balancing<\/text>\n <\/g>\n\n <defs>\n <marker id=\"arrowB2\" markerWidth=\"8\" markerHeight=\"6\" refX=\"4\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#2a5a8c\"\/><\/marker>\n <marker id=\"arrowG4\" markerWidth=\"8\" markerHeight=\"6\" refX=\"4\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#2d6b30\"\/><\/marker>\n <marker id=\"arrowR5\" markerWidth=\"8\" markerHeight=\"6\" refX=\"4\" refY=\"3\" orient=\"auto\"><polygon points=\"0 0, 8 3, 0 6\" fill=\"#b8372b\"\/><\/marker>\n <\/defs>\n <\/svg>\n <p class=\"infographic-note\"><span class=\"legend-blue legend-badge\">Work logic<\/span><span class=\"legend-red legend-badge\">\"Yes\" branch<\/span><span class=\"legend-green legend-badge\">Final check<\/span> Key rule: proceed to alignment only after confirmed soft foot correction. The practical criterion: foot displacement \u2264 0.05 mm during control bolt loosening and absence of anti-phase vibration.<\/p>\n<\/div>\n\n<p>Following this sequence is the foundation for reliable and long-term operation of rotating equipment.<\/p>\n\n<hr>\n\n<footer class=\"article-footer\">\n <p><em>Sources: vibration diagnostics and shaft alignment training program materials; GOST R ISO 20816-1-2021; GOST R ISO 18436-2-2005; ISO 1940-1:2003; VibroMera technical documentation (Balanset-1A).<\/em><\/p>\n<\/footer>\n\n<\/main>\n<\/div>\n\n<script>\n\/\/ Reading progress bar\nwindow.addEventListener('scroll', () => {\n const winHeight = document.documentElement.scrollHeight - document.documentElement.clientHeight;\n const scrolled = (window.scrollY \/ winHeight) * 100;\n document.getElementById('progressBar').style.width = scrolled + '%';\n \n \/\/ Back to top button\n const btn = document.getElementById('backToTop');\n if (window.scrollY > 400) {\n btn.classList.add('visible');\n } else {\n btn.classList.remove('visible');\n }\n});\n\n\/\/ Active TOC highlighting\nconst sections = document.querySelectorAll('h2[id], h3[id]');\nconst tocLinks = document.querySelectorAll('.toc-list a');\n\nconst observer = new IntersectionObserver((entries) => {\n entries.forEach(entry => {\n if (entry.isIntersecting) {\n const id = entry.target.getAttribute('id');\n tocLinks.forEach(link => {\n link.classList.remove('active');\n if (link.getAttribute('data-section') === id) {\n link.classList.add('active');\n }\n });\n }\n });\n}, { rootMargin: '-20% 0px -70% 0px' });\n\nsections.forEach(section => observer.observe(section));\n<\/script>\n\n<\/body>\n<\/html><\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Soft Foot: Causes, Diagnostics and Correction \u2014 Complete Technical Guide VibroMera Technical Knowledge Base Table of Contents 1. Definition & Physical Nature 2. Soft Foot Classification 3. Impact on Vibration Condition 4. Diagnostic Methods 4.1 Static Detection 4.2 Dynamic Detection 4.3 Cross-Phase Analysis 5. Pipe-Induced Soft Foot 6. Contact Area […]<\/p>\n","protected":false},"author":2,"featured_media":100664,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ai_generated_summary":"","footnotes":""},"categories":[54],"tags":[],"class_list":["post-100675","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-content"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/posts\/100675","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/comments?post=100675"}],"version-history":[{"count":4,"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/posts\/100675\/revisions"}],"predecessor-version":[{"id":100962,"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/posts\/100675\/revisions\/100962"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/media\/100664"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/media?parent=100675"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/categories?post=100675"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/bn\/wp-json\/wp\/v2\/tags?post=100675"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}