{"id":100070,"date":"2026-02-15T20:14:53","date_gmt":"2026-02-15T20:14:53","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100070"},"modified":"2026-02-15T20:14:53","modified_gmt":"2026-02-15T20:14:53","slug":"crusher-rotor-balance","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/nb\/calculators\/crusher-rotor-balance\/","title":{"rendered":"Kalkulator for rotorbalanse for knuser | Slag- og kjeveknusere"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Crusher Rotor Balance Calculator\",\"description\":\"Calculate permissible unbalance for crusher rotors per ISO 21940. Supports impact, jaw, and hammer crushers.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/crusher-rotor-balance\/\",\"applicationCategory\":\"Engineering Calculator\",\"operatingSystem\":\"Any\",\"offers\":{\"@type\":\"Offer\",\"price\":\"0\",\"priceCurrency\":\"EUR\"},\"creator\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\"},\"inLanguage\":\"en\",\"isAccessibleForFree\":true}\n<\/script>\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,400&#038;family=JetBrains+Mono:wght@400;500;600&#038;family=Fraunces:opsz,wght@9..144,700;9..144,800&#038;display=swap\" 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tr:nth-child(even){background:var(--vc-surface-alt)}\n.vc-related{display:flex;flex-wrap:wrap;gap:10px;margin-top:16px}\n.vc-related-link{display:inline-block;padding:8px 16px;font-family:var(--vc-font);font-size:13px;font-weight:600;background:var(--vc-surface-alt);color:var(--vc-ink-secondary);border:1px solid var(--vc-border);border-radius:var(--vc-radius);text-decoration:none;transition:all 0.15s}.vc-related-link:hover{border-color:var(--vc-accent);color:var(--vc-accent);background:var(--vc-accent-light)}\n.vc-promo{margin-top:24px;padding:20px;background:linear-gradient(135deg,var(--vc-accent-light),var(--vc-surface));border:1px solid var(--vc-border);border-radius:var(--vc-radius-lg);display:flex;align-items:center;gap:16px}\n.vc-promo-text{flex:1;font-size:14px;color:var(--vc-ink-secondary)}.vc-promo-text strong{color:var(--vc-ink)}\n.vc-promo-link{padding:8px 20px;font-size:13px;font-weight:700;color:#fff;background:var(--vc-accent);border-radius:var(--vc-radius);text-decoration:none;white-space:nowrap;transition:background 0.15s}.vc-promo-link:hover{background:var(--vc-accent-hover)}\n.vc-footer{text-align:center;padding:32px 16px;font-size:13px;color:var(--vc-ink-muted)}.vc-footer a{color:var(--vc-accent);text-decoration:none}.vc-footer a:hover{text-decoration:underline}.vc-footer-links{margin-top:8px;font-size:12px}.vc-footer-links a{margin:0 8px}\n.vc-info-box{background:var(--vc-blue-light);border-left:3px solid var(--vc-blue);padding:14px 16px;border-radius:0 6px 6px 0;margin:14px 0}\n.vc-faq-item{border:1px solid var(--vc-border-light);border-radius:var(--vc-radius);margin-bottom:8px;overflow:hidden}\n.vc-faq-q{width:100%;display:flex;align-items:center;justify-content:space-between;padding:14px 16px;border:none;background:transparent;cursor:pointer;font-family:var(--vc-font);font-size:14px;font-weight:600;text-align:left;color:var(--vc-ink);transition:background 0.15s}\n.vc-faq-q:hover{background:var(--vc-surface-alt)}\n.vc-faq-chevron{width:16px;height:16px;color:var(--vc-ink-muted);transition:transform 0.3s;flex-shrink:0}\n.vc-faq-item.vc-open .vc-faq-chevron{transform:rotate(180deg)}\n.vc-faq-a{max-height:0;overflow:hidden;transition:max-height 0.3s ease}\n.vc-faq-item.vc-open .vc-faq-a{max-height:2000px}\n.vc-faq-a-inner{padding:0 16px 14px;font-size:14px;color:var(--vc-ink-secondary);line-height:1.65}\n.vc-faq-a-inner p{margin:0 0 8px}\n@media print{.vc-section-body{max-height:none!important}.vc-results{max-height:none!important;padding:24px!important}.vc-promo{display:none!important}}\n<\/style>\n\n<div class=\"vc-calculator\" id=\"vc-crusher-balance\">\n\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Free Engineering Tool<\/p>\n    <h1 class=\"vc-header-title\">Crusher Rotor Balance Calculator<\/h1>\n    <p class=\"vc-header-subtitle\">Calculate permissible unbalance for crusher rotors (impact, jaw, hammer crushers) per ISO 21940. Includes per-element tolerance, centrifugal force, and bearing life impact estimates.<\/p>\n    <div class=\"vc-badges\"><span class=\"vc-badge\">ISO 21940<\/span><span class=\"vc-badge\">G16 \u2013 G40<\/span><span class=\"vc-badge\">Bearing Life<\/span><\/div>\n<\/header>\n\n<div class=\"vc-card\">\n    <form class=\"vc-form\" id=\"vc-form\" autocomplete=\"off\">\n        <div class=\"vc-form-grid\">\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-mass\">Rotor Mass <span class=\"vc-label-hint\">(kg)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-mass\" inputmode=\"decimal\" step=\"any\" min=\"0\" placeholder=\"e.g. 3000\" value=\"3000\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-rpm\">Operating Speed <span class=\"vc-label-hint\">(RPM)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-rpm\" inputmode=\"decimal\" step=\"any\" min=\"0\" placeholder=\"e.g. 600\" value=\"600\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-grade\">Balance Grade<\/label>\n                <select class=\"vc-select\" id=\"vc-grade\">\n                    <option value=\"6.3\">G6.3 \u2014 Precision (if required)<\/option>\n                    <option value=\"16\" selected>G16 \u2014 Standard for crushers<\/option>\n                    <option value=\"40\">G40 \u2014 Rough service \/ after hammer change<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-elements\">Number of Hammers\/Blow Bars<\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-elements\" inputmode=\"numeric\" step=\"1\" min=\"1\" placeholder=\"e.g. 4\" value=\"4\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-corr-r\">Correction Radius <span class=\"vc-label-hint\">(mm, typically rotor OD\/2)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-corr-r\" inputmode=\"decimal\" step=\"any\" min=\"0\" placeholder=\"e.g. 600\" value=\"600\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-bearing\">Bearing Dynamic Rating C <span class=\"vc-label-hint\">(kN, optional)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-bearing\" inputmode=\"decimal\" step=\"any\" min=\"0\" placeholder=\"e.g. 500\">\n            <\/div>\n        <\/div>\n    <\/form>\n\n    <div class=\"vc-results vc-visible\" id=\"vc-results\">\n        <div class=\"vc-results-head\">\n            <h2 class=\"vc-results-title\">Results<\/h2>\n            <button type=\"button\" class=\"vc-copy-btn\" id=\"vc-copy-btn\"><svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg> Copy<\/button>\n        <\/div>\n        <div class=\"vc-result-grid\">\n            <div class=\"vc-rcard vc-rcard-primary\"><div class=\"vc-rcard-label\">Permissible Unbalance (Total)<\/div><div class=\"vc-rcard-value\" id=\"vc-r-ubal\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Per-Element Tolerance<\/div><div class=\"vc-rcard-value\" id=\"vc-r-element\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Specific Unbalance (eccentricity)<\/div><div class=\"vc-rcard-value\" id=\"vc-r-ecc\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Centrifugal Force at Tolerance<\/div><div class=\"vc-rcard-value\" id=\"vc-r-force\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Correction Mass at Given Radius<\/div><div class=\"vc-rcard-value\" id=\"vc-r-corrmass\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Bearing Life Impact<\/div><div class=\"vc-rcard-value\" id=\"vc-r-bearing\">\u2014<\/div><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<div class=\"vc-section vc-open\" id=\"vc-sec-theory\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"true\">\n        <span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\ud83d\udcd8<\/span><span class=\"vc-section-title\">Theory &#038; Crusher Guidelines<\/span><\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner vc-theory\">\n            <h3>Key Formulas<\/h3>\n            <div class=\"vc-formula-box\">e_per = G \u00d7 1000 \/ \u03c9 [\u03bcm]<\/div>\n            <div class=\"vc-formula-box\">U_per = e_per \u00d7 M [g\u00b7mm]<\/div>\n            <div class=\"vc-formula-box\">F = M \u00d7 e_per \u00d7 \u03c9\u00b2 \/ 10\u2076 [N]<\/div>\n            <p>Where G is the balance grade (mm\/s), \u03c9 = 2\u03c0\u00d7n\/60 (rad\/s), M is the rotor mass (kg), e_per is the permissible specific unbalance, U_per is the permissible residual unbalance, and F is the resulting centrifugal force.<\/p>\n\n            <h3>Balance Grade Selection for Crushers<\/h3>\n            <table class=\"vc-table\">\n                <thead><tr><th>Crusher Type<\/th><th>Typical Grade<\/th><th>Typical RPM<\/th><\/tr><\/thead>\n                <tbody>\n                    <tr><td>Horizontal shaft impact (HSI)<\/td><td>G16 \u2013 G40<\/td><td>500\u2013800<\/td><\/tr>\n                    <tr><td>Vertical shaft impact (VSI)<\/td><td>G6.3 \u2013 G16<\/td><td>1000\u20132000<\/td><\/tr>\n                    <tr><td>Hammer mill<\/td><td>G16 \u2013 G40<\/td><td>1000\u20131800<\/td><\/tr>\n                    <tr><td>Jaw crusher (flywheel)<\/td><td>G16<\/td><td>200\u2013400<\/td><\/tr>\n                    <tr><td>Cone crusher<\/td><td>G6.3 \u2013 G16<\/td><td>300\u2013600<\/td><\/tr>\n                <\/tbody>\n            <\/table>\n            <h3>Per-Element Mass Tolerance<\/h3>\n            <p>When replacing hammers or blow bars, individual element mass variation contributes\n            directly to rotor unbalance. Each element sits at a specific radius from the rotation\n            axis. The per-element mass tolerance should be:<\/p>\n            <div class=\"vc-formula-box\">\u0394m_element \u2264 U_per \/ (r_element \u00d7 N_elements)<\/div>\n            <p>Where <strong>r_element<\/strong> is the CG radius of the element and <strong>N_elements<\/strong> is the number of elements.<\/p>\n            <h3>Impact on Bearing Life<\/h3>\n            <p>Unbalance force acts as an additional rotating radial load on bearings. The basic\n            bearing rating life (L10) is highly sensitive to applied load:<\/p>\n            <ul>\n                <li><strong>Ball bearings:<\/strong> L10 \u221d (C\/P)\u00b3<\/li>\n                <li><strong>Roller bearings:<\/strong> L10 \u221d (C\/P)^(10\/3)<\/li>\n            <\/ul>\n            <p>Even moderate unbalance forces can significantly reduce bearing life\n            when combined with the already-high process loads in crushers.<\/p>\n            <h3>Practical Balancing Procedure for Crushers<\/h3>\n            <ul>\n                <li><strong>Step 1:<\/strong> Weigh all hammers\/blow bars individually and record masses<\/li>\n                <li><strong>Step 2:<\/strong> Sort elements by mass and pair heaviest with lightest<\/li>\n                <li><strong>Step 3:<\/strong> Install paired elements on opposite sides of the rotor<\/li>\n                <li><strong>Step 4:<\/strong> Verify total mass difference between opposing positions is within per-element tolerance<\/li>\n                <li><strong>Step 5:<\/strong> After installation, run the crusher and measure vibration at both bearings<\/li>\n                <li><strong>Step 6:<\/strong> If vibration exceeds limits, perform single-plane field balancing<\/li>\n            <\/ul>\n\n            <h3>Centrifugal Force and Bearing Life<\/h3>\n            <p>The centrifugal force from unbalance adds a rotating radial load to the bearings. The bearing L10 life relationship is:<\/p>\n            <ul>\n                <li><strong>Ball bearings:<\/strong> L10 = (C\/P)\u00b3 \u00d7 10\u2076 \/ (60 \u00d7 n)<\/li>\n                <li><strong>Roller bearings:<\/strong> L10 = (C\/P)^(10\/3) \u00d7 10\u2076 \/ (60 \u00d7 n)<\/li>\n            <\/ul>\n            <p>Where C is the dynamic load rating, P is the equivalent dynamic load (including unbalance force), and n is RPM. Even a small unbalance force can significantly reduce life when added to the already-high process loads in crushers.<\/p>\n\n            <h3>Vibration Limits for Crushers<\/h3>\n            <p>Due to the inherent impact nature of crushers, vibration limits are higher than for smooth-running machines:<\/p>\n            <ul>\n                <li><strong>Good:<\/strong> &lt; 10 mm\/s velocity RMS on bearing housings<\/li>\n                <li><strong>Acceptable:<\/strong> 10\u201318 mm\/s \u2014 typical for operating crushers<\/li>\n                <li><strong>Alert:<\/strong> 18\u201328 mm\/s \u2014 investigate, check wear items<\/li>\n                <li><strong>Danger:<\/strong> &gt; 28 mm\/s \u2014 shut down and inspect<\/li>\n            <\/ul>\n\n            <h3>Foundation and Structural Considerations<\/h3>\n            <p>Crusher foundations must be designed to absorb impact forces. The foundation mass should be 3\u20135\u00d7 the crusher mass for adequate vibration isolation. Key checks:<\/p>\n            <ul>\n                <li><strong>Anchor bolts:<\/strong> Verify torque at every major maintenance event<\/li>\n                <li><strong>Isolation mounts:<\/strong> Inspect rubber isolators for deterioration and correct deflection<\/li>\n                <li><strong>Concrete condition:<\/strong> Check for cracks, especially around anchor bolt pockets<\/li>\n                <li><strong>Grout integrity:<\/strong> Verify no voids between baseplate and foundation<\/li>\n            <\/ul>\n\n            <h3>Crusher Types and Balance Considerations<\/h3>\n            <ul>\n                <li><strong>Horizontal Shaft Impact (HSI):<\/strong> Blow bars are the primary wear item. Replace as a set and weigh individually. Rotor is typically balanced to G16.<\/li>\n                <li><strong>Vertical Shaft Impact (VSI):<\/strong> Higher speeds demand tighter balance (G6.3\u2013G16). Wear table and anvil ring affect balance indirectly.<\/li>\n                <li><strong>Hammer Mill:<\/strong> Multiple hammers on pivot pins. Reversible hammers must be rotated in matching pairs. G16\u2013G40 depending on speed.<\/li>\n                <li><strong>Jaw Crusher:<\/strong> Flywheel balance is critical. Eccentric shaft unbalance is inherent by design but must be within tolerance.<\/li>\n                <li><strong>Cone Crusher:<\/strong> Mantle and bowl wear affect balance. Head assembly balance is checked during major rebuilds.<\/li>\n            <\/ul>\n\n            <div class=\"vc-info-box\">\n                <p style=\"margin:0;font-size:14px;color:var(--vc-ink-secondary)\"><strong>Best practice:<\/strong> Keep a log of individual hammer\/blow bar masses for each rotor position. Track mass loss over time to predict optimal replacement intervals and maintain balance within tolerance throughout the wear cycle.<\/p>\n            <\/div>\n\n            <div class=\"vc-warning-box\"><p style=\"margin:0;font-size:14px;color:var(--vc-ink-secondary)\"><strong>\u26a0\ufe0f Practical note:<\/strong> After hammer\/blow bar replacement, always weigh individual elements and arrange them for minimum unbalance (heaviest opposite heaviest on opposite sides). Even within G40 tolerance, matching elements extends bearing and frame life considerably.<\/p><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- FAQ -->\n<div class=\"vc-section\" id=\"vc-sec-faq\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\u2753<\/span><span class=\"vc-section-title\">Frequently Asked Questions<\/span><\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-faq-list\" id=\"vc-faq-list\"><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<div class=\"vc-section\" id=\"vc-sec-related\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\ud83d\udd17<\/span><span class=\"vc-section-title\">Related Calculators<\/span><\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\"><div class=\"vc-section-inner\"><div class=\"vc-related\">\n        <a class=\"vc-related-link\" href=\"\/calculators\/residual-unbalance-iso1940\/\">General Residual Unbalance<\/a>\n        <a class=\"vc-related-link\" href=\"\/calculators\/cooling-tower-fan-vibration\/\">Cooling Tower Fan<\/a>\n        <a class=\"vc-related-link\" href=\"\/calculators\/paper-machine-roll-balance\/\">Paper Machine Roll<\/a>\n    <\/div><\/div><\/div>\n<\/div>\n\n<div class=\"vc-promo\"><div class=\"vc-promo-text\"><strong>Vibromera \u2014 Portable Balancing &#038; Vibration Analysis<\/strong><br>Professional field balancing instruments and software. Used in 50+ countries.<\/div><a class=\"vc-promo-link\" href=\"https:\/\/vibromera.eu\/\" target=\"_blank\" rel=\"noopener\">Learn More<\/a><\/div>\n<footer class=\"vc-footer\"><p>\u00a9 2024\u20132025 <a href=\"https:\/\/vibromera.eu\/\">Vibromera<\/a> \u2014 Engineering Calculators<\/p><p style=\"font-size:12px;margin-top:4px;\">Based on ISO 21940. Last updated: February 2025<\/p><div class=\"vc-footer-links\"><a href=\"\/calculators\/engineering-calculators\/\">All Calculators<\/a><a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a><\/div><\/footer>\n\n<\/div>\n\n<script>\n(function(){\n    'use strict';\n    function $(id){return document.getElementById(id)}\n    function fmt(n,d){if(isNaN(n)||!isFinite(n))return'\u2014';return n.toFixed(d===undefined?2:d).replace(\/(\\.\\d*?)0+$\/,'$1').replace(\/\\.$\/,'')}\n\n    function calculate(){\n        var mass=parseFloat($('vc-mass').value);\n        var rpm=parseFloat($('vc-rpm').value);\n        var grade=parseFloat($('vc-grade').value);\n        var elements=parseInt($('vc-elements').value);\n        var corrR=parseFloat($('vc-corr-r').value);\n        var bearingC=parseFloat($('vc-bearing').value);\n\n        if(!mass||mass<=0||!rpm||rpm<=0)return;\n\n        var omega=2*Math.PI*rpm\/60;\n        var eper=grade*1000\/omega;\n        var uper=eper*mass;\n        var force=mass*(eper\/1e6)*omega*omega;\n        var corrMass=(!isNaN(corrR)&&corrR>0)?(uper\/corrR):NaN;\n        var elementTol=(!isNaN(elements)&&elements>0&&!isNaN(corrR)&&corrR>0)?(uper\/(corrR*elements)):NaN;\n\n        $('vc-r-ubal').innerHTML=(uper>=1000?fmt(uper,0):fmt(uper,1))+' <span class=\"vc-rcard-unit\">g\u00b7mm (G'+grade+')<\/span>';\n        $('vc-r-ecc').innerHTML=fmt(eper,1)+' <span class=\"vc-rcard-unit\">\u03bcm<\/span>';\n        $('vc-r-force').innerHTML=fmt(force,0)+' <span class=\"vc-rcard-unit\">N ('+fmt(force\/9.81,1)+' kgf)<\/span>';\n        $('vc-r-corrmass').innerHTML=(!isNaN(corrMass)?fmt(corrMass,1)+' <span class=\"vc-rcard-unit\">g at r='+fmt(corrR,0)+' mm<\/span>':'\u2014');\n        $('vc-r-element').innerHTML=(!isNaN(elementTol)?fmt(elementTol,1)+' <span class=\"vc-rcard-unit\">g max mass difference per element ('+elements+' elements)<\/span>':'\u2014');\n\n        \/\/ Bearing life\n        if(!isNaN(bearingC)&&bearingC>0){\n            var forceKN=force\/1000;\n            var lifeReduction=Math.pow(bearingC\/(bearingC+forceKN),10\/3);\n            $('vc-r-bearing').innerHTML='Unbalance force adds '+fmt(forceKN,2)+' kN \u2192 bearing life reduced to ~'+fmt(lifeReduction*100,0)+'% of rated L10';\n        } else {\n            $('vc-r-bearing').innerHTML='<span class=\"vc-rcard-unit\">Enter bearing C rating to calculate<\/span>';\n        }\n\n        $('vc-results').classList.add('vc-visible');\n    }\n\n    $('vc-form').addEventListener('input',calculate);\n    $('vc-form').addEventListener('change',calculate);\n    $('vc-copy-btn').addEventListener('click',function(){var t='Crusher Rotor Balance\\n\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\nMass: '+$('vc-mass').value+' kg, RPM: '+$('vc-rpm').value+'\\nGrade: G'+$('vc-grade').value+'\\nTotal Unbalance: '+$('vc-r-ubal').textContent+'\\nForce: '+$('vc-r-force').textContent+'\\n\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\nvibromera.eu';if(navigator.clipboard){navigator.clipboard.writeText(t)}});\n    document.querySelectorAll('.vc-section-toggle').forEach(function(btn){btn.addEventListener('click',function(){var s=this.closest('.vc-section');s.classList.toggle('vc-open');this.setAttribute('aria-expanded',s.classList.contains('vc-open'))})});\n\n    \/\/ FAQ\n    var faqData=[\n        {q:'Why use G16 or G40 for crushers instead of G6.3?',a:'<p>Crushers experience massive impact forces during normal operation that dwarf any unbalance forces. The practical benefit of achieving G6.3 is minimal because the process-induced forces are so large. G16 provides a good balance between bearing life protection and practical achievability given the harsh operating conditions and wear.<\/p>'},\n        {q:'How often should crusher rotors be rebalanced?',a:'<p>Rebalance whenever wear items (hammers, blow bars, liners) are replaced, or when vibration at 1\u00d7 RPM exceeds baseline by more than 50%. For impact crushers with replaceable blow bars, this typically means every bar change \u2014 weigh and arrange elements for minimum unbalance.<\/p>'},\n        {q:'Can I field-balance a crusher rotor?',a:'<p>Yes, single-plane field balancing is commonly performed on crusher rotors. Mount a vibration sensor on the drive-end bearing housing, use a keyphasor for phase reference, and run at normal speed (with no feed). The trial-weight method works well. Correction weights can be welded to the rotor end plates.<\/p>'},\n        {q:'What about two-plane balancing for crushers?',a:'<p>Two-plane (couple) balancing is generally not required for crusher rotors because their L\/D ratio is typically low (disc-like). Single-plane balancing is sufficient. However, if you see significant phase differences between bearings, two-plane balancing may help.<\/p>'},\n        {q:'How does hammer wear affect balance?',a:'<p>As hammers wear, they lose mass unevenly. The rotor becomes progressively more unbalanced. Monitor vibration at 1\u00d7 and trend over time. When vibration reaches the alert level or when hammer tips are worn to the rotation limit, it is time to replace and rebalance.<\/p>'},\n        {q:'What vibration level is normal for a crusher?',a:'<p>Crushers have inherently high vibration due to the impact process. Bearing housing velocity below 10 mm\/s RMS is considered good. Between 10\u201318 mm\/s is acceptable for most crushers during normal operation. Above 18 mm\/s warrants investigation, and above 28 mm\/s is a danger level requiring shutdown.<\/p>'},\n        {q:'How do I reduce vibration on an impact crusher?',a:'<p>1) Match blow bar masses within tolerance. 2) Ensure all blow bars are seated properly with no gaps. 3) Check for worn rotor side plates. 4) Verify bearing condition and clearances. 5) Inspect foundation bolts for looseness. 6) If 1\u00d7 vibration is dominant, perform field balancing. 7) Check drive components (belts, sheaves, coupling) for wear.<\/p>'},\n        {q:'What bearing type is typically used in crushers?',a:'<p>Most crushers use spherical roller bearings (SRB) due to their ability to handle both radial and axial loads as well as shaft misalignment from housing deflection. These have an L10 life exponent of 10\/3. The dynamic load rating C is typically 500\u20132000 kN depending on crusher size.<\/p>'},\n        {q:'Should I balance the rotor with hammers in the \"new\" or \"worn\" position?',a:'<p>Balance with hammers in the position they will operate in. If hammers are reversible, balance in the initial operating position. When hammers are reversed to use the second edge, re-check balance. Some operations balance at mid-life mass to optimize the average unbalance over the full wear cycle.<\/p>'},\n        {q:'What safety precautions are needed for crusher balancing?',a:'<p>Crusher rotors are heavy and have stored energy. Key precautions: 1) Lock out\/tag out all energy sources. 2) Use proper rigging when handling blow bars\/hammers. 3) For field balancing, ensure the crusher chamber is empty and guards are in place. 4) Never run a crusher above rated speed. 5) Keep personnel clear of the discharge area during trial runs.<\/p>'},\n        {q:'How does foundation condition affect crusher vibration?',a:'<p>A deteriorated foundation amplifies vibration from all sources including unbalance. Check for: cracked concrete, loose anchor bolts, grout deterioration, and soil erosion under the foundation. Foundation natural frequency should be well separated from 1\u00d7 RPM. A foundation assessment is recommended if vibration suddenly increases without rotor changes.<\/p>'}\n    ];\n    var faqList=$('vc-faq-list');\n    faqData.forEach(function(faq){faqList.innerHTML+='<div class=\"vc-faq-item\"><button type=\"button\" class=\"vc-faq-q\"><span>'+faq.q+'<\/span><svg class=\"vc-faq-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button><div class=\"vc-faq-a\"><div class=\"vc-faq-a-inner\">'+faq.a+'<\/div><\/div><\/div>'});\n    faqList.addEventListener('click',function(e){var btn=e.target.closest('.vc-faq-q');if(!btn)return;btn.closest('.vc-faq-item').classList.toggle('vc-open')});\n\n    calculate();\n})();\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Gratis online kalkulator for rotorbalanse i knuser. Beregn tillatt ubalanse (G16\u2013G40), toleranse per element, sentrifugalkraft og levetid for lagrene for slagknusere og kjeftknusere.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100070","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100070","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":1,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100070\/revisions"}],"predecessor-version":[{"id":100385,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100070\/revisions\/100385"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/media?parent=100070"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/categories?post=100070"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/tags?post=100070"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}