{"id":100276,"date":"2026-02-15T20:31:30","date_gmt":"2026-02-15T20:31:30","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100276"},"modified":"2026-07-16T01:39:11","modified_gmt":"2026-07-16T01:39:11","slug":"v-belt-calculator","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/pl\/calculators\/v-belt-calculator\/","title":{"rendered":"V-Belt Catalog Rating and Geometry Calculator"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"V-Belt Catalog Rating and Geometry Calculator\",\"description\":\"Source-controlled V-belt drive geometry and catalog-rating checker. 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details:first-child{border-top:0}\n#vbm-vbelt summary{padding:14px 0;cursor:pointer;font-weight:800}\n#vbm-vbelt details p{margin:0 0 15px}\n#vbm-vbelt .vb-needs{padding:13px 15px;border:1px solid #efd794;border-radius:7px;background:var(--vb-warn-bg);color:#664a0c;font-size:13px}\n#vbm-vbelt footer{padding:28px 16px;text-align:center;color:var(--vb-muted);font-size:12px}\n@media(max-width:760px){#vbm-vbelt .vb-grid,#vbm-vbelt .vb-result-grid{grid-template-columns:1fr}#vbm-vbelt .vb-result-main{grid-column:1}#vbm-vbelt .vb-body,#vbm-vbelt .vb-results,#vbm-vbelt .vb-section-in{padding:17px}#vbm-vbelt .vb-card-head,#vbm-vbelt .vb-section h2{padding:16px 17px}}\n@media print{#vbm-vbelt .vb-actions{display:none}#vbm-vbelt .vb-card{box-shadow:none}#vbm-vbelt .vb-results{display:block}}\n<\/style>\n\n<div id=\"vbm-vbelt\">\n  <header class=\"vb-head\">\n    <p class=\"vb-eyebrow\">Engineering reference &#8211; source controlled<\/p>\n    <h1>V-Belt Catalog Rating and Geometry Calculator<\/h1>\n    <p class=\"vb-sub\">For an open, two-pulley reduction drive with the smaller pulley driving. The tool calculates geometry and applies power ratings only when you enter the exact values from one identified manufacturer catalog.<\/p>\n    <div class=\"vb-tags\"><span class=\"vb-tag\">ISO scope corrected<\/span><span class=\"vb-tag\">No invented power table<\/span><span class=\"vb-tag\">Explicit calculation<\/span><\/div>\n  <\/header>\n\n  <div class=\"vb-callout\"><strong>Do not use the old result.<\/strong> ISO 4184:2025 specifies requirements for classical and narrow V-belts and their datum-length system; it is not a universal belt-power selection table. ISO 5288:2024 is vocabulary for synchronous belt drives and is not applicable to this V-belt calculation. Final profile, pulley, length, tension, shaft load, guarding and environmental suitability must be verified in the current manufacturer procedure.<\/div>\n\n  <section class=\"vb-card\" aria-labelledby=\"vb-input-title\">\n    <div class=\"vb-card-head\"><h2 id=\"vb-input-title\">Calculation record<\/h2><p>All fields are required. Decimal point and decimal comma are accepted; grouped numbers and unit suffixes are rejected.<\/p><\/div>\n    <div class=\"vb-body\">\n      <form id=\"vb-form\" novalidate autocomplete=\"off\">\n        <div class=\"vb-grid\">\n          <div>\n            <label for=\"vb-power-unit\">Power unit<\/label>\n            <select id=\"vb-power-unit\"><option value=\"kw\">kW<\/option><option value=\"hp\">mechanical hp<\/option><\/select>\n          <\/div>\n          <div>\n            <label for=\"vb-length-unit\">Diameter and centre-distance unit<\/label>\n            <select id=\"vb-length-unit\"><option value=\"mm\">mm<\/option><option value=\"in\">in<\/option><\/select>\n          <\/div>\n          <div>\n            <label for=\"vb-power\">Transmitted power, P<\/label>\n            <input id=\"vb-power\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 132\">\n            <span class=\"vb-hint\">Rated or otherwise defined power required by the chosen catalog method.<\/span>\n          <\/div>\n          <div>\n            <label for=\"vb-service\">Catalog service\/load factor, c2<\/label>\n            <input id=\"vb-service\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 1.3\">\n            <span class=\"vb-hint\">Copy from the same manufacturer method; do not infer it from a generic machine label.<\/span>\n          <\/div>\n          <div>\n            <label for=\"vb-speed\">Small driver pulley speed, n1 (rpm)<\/label>\n            <input id=\"vb-speed\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 1485\">\n          <\/div>\n          <div>\n            <label for=\"vb-d1\">Small driver datum diameter, d1<\/label>\n            <input id=\"vb-d1\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 280\">\n            <span class=\"vb-hint\">Use datum diameter, not outside diameter.<\/span>\n          <\/div>\n          <div>\n            <label for=\"vb-d2\">Large driven datum diameter, d2<\/label>\n            <input id=\"vb-d2\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 500\">\n          <\/div>\n          <div>\n            <label for=\"vb-centre\">Shaft centre distance, a<\/label>\n            <input id=\"vb-centre\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 1383.5\">\n          <\/div>\n          <div>\n            <label for=\"vb-nominal\">Catalog nominal power per belt, PN<\/label>\n            <input id=\"vb-nominal\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 21.87\">\n            <span class=\"vb-hint\">For the exact profile, datum diameter, speed, ratio, belt family and catalog basis.<\/span>\n          <\/div>\n          <div>\n            <label for=\"vb-arc\">Catalog arc-of-contact factor, c1<\/label>\n            <input id=\"vb-arc\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 1.0\">\n            <span class=\"vb-hint\">Must be greater than 0 and no greater than 1 for this restricted method.<\/span>\n          <\/div>\n          <div>\n            <label for=\"vb-length-factor\">Catalog belt-length factor, c3<\/label>\n            <input id=\"vb-length-factor\" type=\"text\" inputmode=\"decimal\" maxlength=\"40\" placeholder=\"e.g. 1.02\">\n          <\/div>\n          <div class=\"vb-field-wide\">\n            <label for=\"vb-source\">Exact rating source record<\/label>\n            <textarea id=\"vb-source\" maxlength=\"500\" placeholder=\"Manufacturer, document title\/revision\/date, product family\/profile, page and table\/software version\"><\/textarea>\n          <\/div>\n        <\/div>\n\n        <fieldset>\n          <legend>Required confirmations<\/legend>\n          <label class=\"vb-check\"><input id=\"vb-confirm-source\" type=\"checkbox\"><span>I copied PN, c1, c2 and c3 from the same identified manufacturer method and matched its belt family, profile, diameter, speed, ratio, length and units.<\/span><\/label>\n          <label class=\"vb-check\"><input id=\"vb-confirm-scope\" type=\"checkbox\"><span>This is an open two-pulley reduction drive; d1 is the smaller driving datum diameter, d2 is the larger driven datum diameter, and a is the shaft centre distance.<\/span><\/label>\n          <label class=\"vb-check\"><input id=\"vb-confirm-review\" type=\"checkbox\"><span>I will verify the selected standard\/catalog length, minimum pulley diameter, permissible belt speed, tension, shaft loads, matched set, environment, dynamic balance, alignment, guarding and final engineering approval.<\/span><\/label>\n        <\/fieldset>\n\n        <div class=\"vb-actions\">\n          <button class=\"vb-primary\" type=\"submit\">Calculate from record<\/button>\n          <button class=\"vb-secondary\" type=\"button\" id=\"vb-example\">Load published Optibelt example<\/button>\n          <button class=\"vb-secondary\" type=\"button\" id=\"vb-clear\">Clear<\/button>\n        <\/div>\n        <div class=\"vb-errors\" id=\"vb-errors\" role=\"alert\" aria-live=\"assertive\" tabindex=\"-1\"><\/div>\n        <div class=\"vb-status\" id=\"vb-status\" aria-live=\"polite\"><\/div>\n      <\/form>\n    <\/div>\n\n    <div class=\"vb-results\" id=\"vb-results\" aria-live=\"polite\">\n      <div class=\"vb-result-grid\">\n        <div class=\"vb-result vb-result-main\"><div class=\"vb-result-label\">Preliminary belt quantity<\/div><div class=\"vb-result-value\" id=\"vb-out-belts\">&#8211;<\/div><div class=\"vb-result-note\">The raw calculated ratio is rounded upward; this is not final drive approval.<\/div><\/div>\n        <div class=\"vb-result\"><div class=\"vb-result-label\">Calculated belt ratio, zth<\/div><div class=\"vb-result-value\" id=\"vb-out-zraw\">&#8211;<\/div><\/div>\n        <div class=\"vb-result\"><div class=\"vb-result-label\">Design power, PB<\/div><div class=\"vb-result-value\" id=\"vb-out-design\">&#8211;<\/div><\/div>\n        <div class=\"vb-result\"><div class=\"vb-result-label\">Corrected capacity per belt<\/div><div class=\"vb-result-value\" id=\"vb-out-capacity\">&#8211;<\/div><\/div>\n        <div class=\"vb-result\"><div class=\"vb-result-label\">Nominal ratio \/ driven speed<\/div><div class=\"vb-result-value\" id=\"vb-out-ratio\">&#8211;<\/div><\/div>\n        <div class=\"vb-result\"><div class=\"vb-result-label\">Belt speed<\/div><div class=\"vb-result-value\" id=\"vb-out-speed\">&#8211;<\/div><\/div>\n        <div class=\"vb-result\"><div class=\"vb-result-label\">Small-pulley wrap angle<\/div><div class=\"vb-result-value\" id=\"vb-out-wrap\">&#8211;<\/div><\/div>\n        <div class=\"vb-result\"><div class=\"vb-result-label\">Theoretical datum length<\/div><div class=\"vb-result-value\" id=\"vb-out-length\">&#8211;<\/div><div class=\"vb-result-note\" id=\"vb-out-length-note\"><\/div><\/div>\n      <\/div>\n      <div class=\"vb-source-echo\"><strong>Rating source entered:<\/strong> <span id=\"vb-out-source\"><\/span><\/div>\n      <div class=\"vb-safety\"><strong>Stop before procurement or operation.<\/strong> The result does not select an ISO\/catalog belt length, verify a pulley profile, calculate installation tension, confirm shaft or bearing loads, assess torsional dynamics, or establish guarding and lockout procedures. Complete the manufacturer&#8217;s design process and an engineering review.<\/div>\n    <\/div>\n  <\/section>\n\n  <section class=\"vb-section\">\n    <h2>Formulas and scope<\/h2>\n    <div class=\"vb-section-in\">\n      <p>These equations are the open-belt geometry and catalog-rating workflow shown in the official Optibelt technical manual. They are not described here as formulas from ISO 4184.<\/p>\n      <h3>Catalog rating<\/h3>\n      <div class=\"vb-formula\">PB = P * c2<\/div>\n      <div class=\"vb-formula\">Pcorrected = PN * c1 * c3<\/div>\n      <div class=\"vb-formula\">zth = PB \/ Pcorrected ; z = ceil(zth)<\/div>\n      <p>PN and the factors are product- and manufacturer-specific. Mixing values from different catalogs or belt families invalidates the result.<\/p>\n      <h3>Ratio, speed and open-belt geometry<\/h3>\n      <div class=\"vb-formula\">i = d2 \/ d1 ; n2 = n1 \/ i<\/div>\n      <div class=\"vb-formula\">v = pi * d1 * n1 \/ 60000 &nbsp; [d1 in mm, n1 in rpm, v in m\/s]<\/div>\n      <div class=\"vb-formula\">alpha = asin((d2 &#8211; d1) \/ (2a)) ; beta = pi &#8211; 2alpha<\/div>\n      <div class=\"vb-formula\">Ld = 2a*cos(alpha) + (pi\/2)(d1 + d2) + alpha(d2 &#8211; d1)<\/div>\n      <div class=\"vb-formula\">Ld,approx = 2a + (pi\/2)(d1 + d2) + (d2 &#8211; d1)^2 \/ (4a)<\/div>\n      <p>Diameters and centre distance must use one consistent length unit; the calculator converts to millimetres. The theoretical datum length must be replaced by an available standard\/catalog length and the final centre distance must then be recalculated in the manufacturer&#8217;s procedure.<\/p>\n    <\/div>\n  <\/section>\n\n  <section class=\"vb-section\">\n    <h2>Standards and source boundary<\/h2>\n    <div class=\"vb-section-in\">\n      <p><em>On a small screen, scroll the source table horizontally.<\/em><\/p>\n      <div class=\"vb-table-wrap\" tabindex=\"0\" aria-label=\"Standards and source boundary table; scroll horizontally on small screens\"><table>\n        <thead><tr><th>Source<\/th><th>Status checked 16 July 2026<\/th><th>What it supports here<\/th><th>What it does not support here<\/th><\/tr><\/thead>\n        <tbody>\n          <tr><td><a href=\"https:\/\/www.iso.org\/standard\/88704.html\" target=\"_blank\" rel=\"noopener\">ISO 4184:2025<\/a>, Edition 3<\/td><td>Published, October 2025; replaces ISO 4184:1992<\/td><td>Requirements for classical sections Y-Z-A-B-C-D-E and narrow sections SPZ-SPA-SPB-SPC; datum-length system.<\/td><td>No universal service factor, belt power rating, profile recommendation or belt-count table is inferred from its public record.<\/td><\/tr>\n          <tr><td><a href=\"https:\/\/www.iso.org\/standard\/88705.html\" target=\"_blank\" rel=\"noopener\">ISO 4183:2026<\/a>, Edition 4<\/td><td>Published, January 2026; replaces ISO 4183:1995<\/td><td>Principal pulley-groove dimensions in the datum-width system.<\/td><td>Not a universal drive power-rating method.<\/td><\/tr>\n          <tr><td><a href=\"https:\/\/www.iso.org\/standard\/59452.html\" target=\"_blank\" rel=\"noopener\">ISO 1081:2013<\/a>, Edition 3<\/td><td>Published but marked &#8220;to be revised&#8221;; ISO\/DIS 1081 under development<\/td><td>Vocabulary and the distinction between datum-width and effective-width systems.<\/td><td>Does not make values from the two systems interchangeable.<\/td><\/tr>\n          <tr><td><a href=\"https:\/\/www.iso.org\/standard\/89598.html\" target=\"_blank\" rel=\"noopener\">ISO 5288:2024<\/a>, Edition 4<\/td><td>Published, November 2024<\/td><td>Synchronous-belt vocabulary only.<\/td><td>Not applicable as the selection standard for this friction V-belt drive.<\/td><\/tr>\n          <tr><td><a href=\"https:\/\/www.optibelt.com\/fileadmin\/pdf\/produkte\/keilriemen\/Optibelt-TM-v-belt-drives.pdf\" target=\"_blank\" rel=\"noopener\">Optibelt Technical Manual &#8211; V-Belt Drives<\/a><\/td><td>Official manufacturer PDF retrieved 16 July 2026; PDF metadata modified 22 January 2024<\/td><td>Pages 72 and 83-85 show the catalog factors, geometry, published example and z = P*c2\/(PN*c1*c3).<\/td><td>Its ratings and factors must not be presented as universal values for other manufacturers.<\/td><\/tr>\n        <\/tbody>\n      <\/table><\/div>\n      <p class=\"vb-needs\"><strong>NEEDS_LICENSED_SOURCE:<\/strong> the exact ISO 4184:2025 standard datum-length series, tolerances and measurement conditions are not reproduced. Use a licensed copy and the applicable manufacturer catalog before selecting a purchasable belt.<\/p>\n    <\/div>\n  <\/section>\n\n  <section class=\"vb-section\">\n    <h2>Published example check<\/h2>\n    <div class=\"vb-section-in\">\n      <p>Optibelt&#8217;s pages 83-85 use P = 132 kW, c2 = 1.3, d1 = 280 mm, d2 = 500 mm, n1 = 1485 rpm, a = 1383.5 mm, PN = 21.87 kW\/belt, c1 = 1.00 and c3 = 1.02. The published belt-count ratio is 7.69 and the recommendation is eight SPB belts for that identified example. Using unrounded inputs here gives zth = 7.692515, belt speed 21.771 m\/s and a theoretical datum length about 4000.972 mm. The example button loads these values but deliberately does not check the required confirmations.<\/p>\n    <\/div>\n  <\/section>\n\n  <section class=\"vb-section\">\n    <h2>Questions and limitations<\/h2>\n    <div class=\"vb-section-in\">\n      <details><summary>Why is there no automatic profile recommendation?<\/summary><p>A power range alone is insufficient. Profile selection depends on the manufacturer&#8217;s rating chart or software, speed, pulley diameter, ratio, belt length, duty, environment and product family. The old generic ranges had no controlled source.<\/p><\/details>\n      <details><summary>Why must all catalog factors come from one source?<\/summary><p>The nominal power rating is established under stated reference conditions. Arc, length and service factors correct that specific basis. Combining unrelated tables can double-count or omit corrections.<\/p><\/details>\n      <details><summary>Does the calculated quantity approve the drive?<\/summary><p>No. It is only the upward-rounded catalog capacity ratio after the entered factors. Final selection still requires the complete manufacturer procedure, tension and shaft-load checks, standard\/catalog length selection, dynamics and safety review.<\/p><\/details>\n      <details><summary>Can I use outside pulley diameters?<\/summary><p>No. This restricted calculator requires datum diameters. ISO 1081 distinguishes datum-width and effective-width systems; outside, datum and effective diameters are not interchangeable without the applicable product data.<\/p><\/details>\n    <\/div>\n  <\/section>\n\n  <footer>Scientific audit revision: 16 July 2026. Reference calculation only; not an ISO certification or a substitute for manufacturer design approval.<\/footer>\n<\/div>\n\n<script>\n(function(){\n  'use strict';\n  var HP_TO_KW=0.7456998715822702,IN_TO_MM=25.4;\n  function byId(id){return document.getElementById(id)}\n  var form=byId('vb-form'),results=byId('vb-results'),errors=byId('vb-errors'),status=byId('vb-status');\n  function parseDecimal(raw){\n    var s=String(raw==null?'':raw).trim();\n    if(!s||s.length>40||!\/^(?:\\d+(?:[.,]\\d*)?|[.,]\\d+)$\/.test(s))return null;\n    var n=Number(s.replace(',','.'));\n    return Number.isFinite(n)?n:null;\n  }\n  function readPositive(id,label,max,list){\n    var n=parseDecimal(byId(id).value);\n    if(n===null||n<=0||n>max){list.push(label+' must be a complete positive decimal no greater than '+max+'.');return null}\n    return n;\n  }\n  function fmt(n,d){\n    if(!Number.isFinite(n))return '-';\n    return n.toLocaleString('en-US',{minimumFractionDigits:0,maximumFractionDigits:d});\n  }\n  function hideResult(message){results.classList.remove('vb-show');if(message)status.textContent=message}\n  function showErrors(list){\n    errors.textContent='';\n    if(!list.length){errors.classList.remove('vb-show');return}\n    var strong=document.createElement('strong');strong.textContent='Calculation not performed.';errors.appendChild(strong);\n    var ul=document.createElement('ul');list.forEach(function(x){var li=document.createElement('li');li.textContent=x;ul.appendChild(li)});errors.appendChild(ul);errors.classList.add('vb-show');errors.focus();\n  }\n  function compute(x){\n    var design=x.powerKw*x.service;\n    var ratio=x.d2mm\/x.d1mm;\n    var driven=x.rpm\/ratio;\n    var speed=Math.PI*x.d1mm*x.rpm\/60000;\n    var tangent=(x.d2mm-x.d1mm)\/(2*x.centreMm);\n    var alpha=Math.asin(tangent);\n    var wrap=Math.PI-2*alpha;\n    var exactLength=2*x.centreMm*Math.cos(alpha)+(Math.PI\/2)*(x.d1mm+x.d2mm)+alpha*(x.d2mm-x.d1mm);\n    var approximateLength=2*x.centreMm+(Math.PI\/2)*(x.d1mm+x.d2mm)+Math.pow(x.d2mm-x.d1mm,2)\/(4*x.centreMm);\n    var capacity=x.nominalKw*x.arc*x.lengthFactor;\n    var zRaw=design\/capacity;\n    return {design:design,ratio:ratio,driven:driven,speed:speed,tangent:tangent,wrapDeg:wrap*180\/Math.PI,exactLength:exactLength,approximateLength:approximateLength,capacity:capacity,zRaw:zRaw,belts:Math.ceil(zRaw)};\n  }\n  form.addEventListener('submit',function(ev){\n    ev.preventDefault();\n    var list=[];\n    var power=readPositive('vb-power','Transmitted power',1e9,list);\n    var service=readPositive('vb-service','Service\/load factor c2',10,list);\n    var rpm=readPositive('vb-speed','Small driver speed',1e7,list);\n    var d1=readPositive('vb-d1','Small driver datum diameter',1e8,list);\n    var d2=readPositive('vb-d2','Large driven datum diameter',1e8,list);\n    var centre=readPositive('vb-centre','Shaft centre distance',1e9,list);\n    var nominal=readPositive('vb-nominal','Catalog nominal power per belt PN',1e9,list);\n    var arc=readPositive('vb-arc','Arc-of-contact factor c1',1,list);\n    var lengthFactor=readPositive('vb-length-factor','Belt-length factor c3',10,list);\n    var source=byId('vb-source').value.trim();\n    if(source.length<12)list.push('Enter an exact manufacturer document or software source record (at least 12 characters).');\n    if(!byId('vb-confirm-source').checked)list.push('Confirm that all catalog ratings and factors use one matched source and basis.');\n    if(!byId('vb-confirm-scope').checked)list.push('Confirm the restricted open reduction-drive geometry and datum-diameter inputs.');\n    if(!byId('vb-confirm-review').checked)list.push('Confirm the remaining manufacturer and engineering review.');\n    var powerScale=byId('vb-power-unit').value==='hp'?HP_TO_KW:1;\n    var lengthScale=byId('vb-length-unit').value==='in'?IN_TO_MM:1;\n    var x=null;\n    if(!list.length){\n      x={powerKw:power*powerScale,service:service,rpm:rpm,d1mm:d1*lengthScale,d2mm:d2*lengthScale,centreMm:centre*lengthScale,nominalKw:nominal*powerScale,arc:arc,lengthFactor:lengthFactor,source:source};\n      if(x.d2mm<x.d1mm)list.push('d2 must be greater than or equal to d1; this tool is restricted to a reduction drive with the smaller pulley driving.');\n      if((x.d2mm-x.d1mm)\/(2*x.centreMm)>=1)list.push('Centre distance must be greater than (d2 - d1)\/2 so the open-belt tangent geometry exists.');\n    }\n    if(list.length){showErrors(list);hideResult('Correct the record and submit again.');return}\n    var r=compute(x);\n    if(!Object.keys(r).every(function(k){return Number.isFinite(r[k])})||r.belts<1||!Number.isSafeInteger(r.belts)){\n      showErrors(['The entered combination produces an unsupported non-finite or excessively large result.']);hideResult('No result retained.');return;\n    }\n    showErrors([]);\n    var selectedPower=byId('vb-power-unit').value,selectedLength=byId('vb-length-unit').value;\n    var designSelected=selectedPower==='hp'?r.design\/HP_TO_KW:r.design;\n    var capacitySelected=selectedPower==='hp'?r.capacity\/HP_TO_KW:r.capacity;\n    var exactSelected=selectedLength==='in'?r.exactLength\/IN_TO_MM:r.exactLength;\n    var approxSelected=selectedLength==='in'?r.approximateLength\/IN_TO_MM:r.approximateLength;\n    byId('vb-out-belts').textContent=String(r.belts)+' belts';\n    byId('vb-out-zraw').textContent=fmt(r.zRaw,6);\n    byId('vb-out-design').textContent=fmt(designSelected,6)+' '+(selectedPower==='hp'?'hp':'kW');\n    byId('vb-out-capacity').textContent=fmt(capacitySelected,6)+' '+(selectedPower==='hp'?'hp':'kW')+'\/belt';\n    byId('vb-out-ratio').textContent=fmt(r.ratio,6)+' \/ '+fmt(r.driven,3)+' rpm';\n    byId('vb-out-speed').textContent=fmt(r.speed,6)+' m\/s';\n    byId('vb-out-wrap').textContent=fmt(r.wrapDeg,6)+' deg';\n    byId('vb-out-length').textContent=fmt(exactSelected,6)+' '+(selectedLength==='in'?'in':'mm');\n    byId('vb-out-length-note').textContent='Open-belt approximation: '+fmt(approxSelected,6)+' '+(selectedLength==='in'?'in':'mm')+'; difference '+fmt(Math.abs(approxSelected-exactSelected),6)+' '+(selectedLength==='in'?'in':'mm')+'.';\n    byId('vb-out-source').textContent=source;\n    results.classList.add('vb-show');status.textContent='Calculated from the submitted source-controlled record.';results.scrollIntoView({behavior:'smooth',block:'start'});\n  });\n  form.addEventListener('input',function(){if(results.classList.contains('vb-show'))hideResult('Inputs changed. Submit again to create a current result.');showErrors([])});\n  form.addEventListener('change',function(){if(results.classList.contains('vb-show'))hideResult('Inputs changed. Submit again to create a current result.');showErrors([])});\n  byId('vb-example').addEventListener('click',function(){\n    byId('vb-power-unit').value='kw';byId('vb-length-unit').value='mm';\n    byId('vb-power').value='132';byId('vb-service').value='1.3';byId('vb-speed').value='1485';byId('vb-d1').value='280';byId('vb-d2').value='500';byId('vb-centre').value='1383.5';byId('vb-nominal').value='21.87';byId('vb-arc').value='1.0';byId('vb-length-factor').value='1.02';\n    byId('vb-source').value='Optibelt Technical Manual - V-Belt Drives, PDF modified 2024-01-22, pages 83-85, SPB example; PN from table 43, c1\/c3 from tables 22\/24.';\n    byId('vb-confirm-source').checked=false;byId('vb-confirm-scope').checked=false;byId('vb-confirm-review').checked=false;\n    showErrors([]);hideResult('Published example loaded. Review the source and check all three confirmations before calculating.');\n  });\n  byId('vb-clear').addEventListener('click',function(){form.reset();showErrors([]);hideResult('Record cleared.');byId('vb-power').focus()});\n})();\n<\/script>\n\n","protected":false},"excerpt":{"rendered":"<p>Calculate open V-belt geometry and preliminary belt quantity only from one identified manufacturer catalog; no generic profile or power table is generated.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100276","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/calculator\/100276","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":3,"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/calculator\/100276\/revisions"}],"predecessor-version":[{"id":102618,"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/calculator\/100276\/revisions\/102618"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/media?parent=100276"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/categories?post=100276"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/pl\/wp-json\/wp\/v2\/tags?post=100276"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}