V Belt Troubleshooting
Premature Drive V Belt Failure
| Symptoms | Probable Cause | Corrective Action |
| Broken belts | Under-designed drive | Redesign the drive |
| Belt rolled or pried onto sheave | Use drive take-up when installing | |
| Object falling into drive | Provide adequate guards or drive protection methods | |
| Severe shock load | Redesign the drive to accommodate shock load | |
| Belts fail to carry a load No visible reason shown |
Under-designed drive | Redesign the drive |
| There is a damaged tensile member | Follow the correct installation procedures | |
| There are worn sheave grooves present | Check for groove wear – Replace as needed | |
| Center distance movement | Check the drive for center distance movement while running | |
| Edge cord failure | There is Pulley misalignment | Check the pulley alignment and correct |
| Damaged tensile member | Follow the correct installation procedure | |
| Belt De-lamination or undercord separation | Too small sheaves | Check Drive Design. Replace with larger sheaves |
| Use of too small of a backside idler | Increase the backside idler to an acceptable diameter |
Severe or Abnormal V-Belt Wear
| Symptoms | Probable Cause | Corrective Action |
| Wear is found on the top surface of the belt | Rubbing against the drive guard | Repair or replace the dive belt guard |
| Idler malfunction | Replace the faulty idler | |
| There is wear on the top corners of the belt | Belt-to-sheave fit is incorrect – belt too small for the groove | Use the correct belt to sheave combination |
| Wear was found on the belt sidewalls | Belt Slip | Retention until the slipping stops |
| Misalignment | Realign the sheaves | |
| Worn sheaves | Replace the sheaves | |
| Incorrect Belt | Replace with the correct belt size | |
| There is wear on the bottom corner of the belt | Belt to sheave combination fit is incorrect | Use the correct belt-to-sheave combination for the drive |
| Worn sheaves | Replace sheaves | |
| There is wear on the bottom surface of the belt | Belt bottoming out on the sheave groove | Use the correct belt to sheave match for your system |
| Worn sheaves | Replace the sheaves | |
| Debris in the sheaves | Clean the sheaves | |
| Undercord Cracking can be detected | The sheave is diameter too small | Use larger diameter sheaves |
| Belt Slip | Re-tension the belt and system | |
| Backside idler too small | Use a larger diameter backside idler | |
| Improper storage of the belts | Do not coil the belt too tightly, kink or bend – Avoid heat and direct sunlight | |
| Under-cord or sidewall burn or hardening | Belt slipping | Re-tension until the slipping stops |
| Worn sheaves | Replace sheaves | |
| Under-designed Drive | Redesign the drive to accomplish task | |
| Shaft movement | Check for center distance changes | |
| Belt surface hard or still | Hot drive environment | Improve ventilation to the drive belt |
| Belt surface flaking, sticky or swollen | Oil or chemical contamination | Do not use belt dressing -Eliminate sources of oil, grease, or chemical contamination |
V Belts Turn Over or Come Off Drive
| Symptoms | Probable Cause | Corrective Action |
| Involving Single or Multiple drive belts | Shock loading or vibration | Check the drive design and be sure you are using a high quality belt |
| Foreign material in grooves | Shield the grooves and drive from falling materials | |
| Misaligned sheaves | Realign the sheaves | |
| Worn sheave grooves | Replace the sheaves | |
| Damaged tensile member | Use the correct belt installation and storage procedures | |
| Incorrectly placed flat idler | Carefully align the flat idler on the slack side of the drive as close as possible to the driver sheaves | |
| Mismatched belt sets | Replace with a new set of matched belts – DO NOT mix and match old and new belts | |
| poor drive design | Check for center distance stability and vibration dampening |
Belt Stretches Beyond Available Take-Up
| Symptoms | Probable Cause | Corrective Action |
| Multiple belts stretch unequally | Misaligned belt drive | Realign and re-tension drive |
| Debris in the sheaves | Clean the sheave | |
| Broken tensile member or cord damaged | Replace all the belts and make sure they are installed properly | |
| Mismatched belt set | Install a matched set of new belts | |
| Single belt or where all belts stretch evenly | Insufficient take-up allowance | Check the Take Up > use the allowances in the manual |
| Grossly overloaded or under-designed drive | Redesign the drive | |
| Broken tensile members | Replace the belt / belts with new |
Drive Belt Noise
| Symptoms | Probable Cause | Corrective Action |
| Belt squeals or chirps | Belt slip | Re-tension |
| Contamination | Clean belts and sheaves | |
| Slapping sound | Loose belts | Re-tension |
| Mismatched belt set | Install a new matched set of belts | |
| Misalignment | Realign belts so all belts are sharing the load equally | |
| Rubbing sounds | Guard interference | Repair, replace or redesign the belt guard |
| Grinding sounds | Damaged bearings | Replace > Align > Lubricate Bearings |
| Unusually loud drive | Incorrect belt | Use correct belt cross section in pulley – Use correct tooth profile and pitch in sprocket |
| Incorrect tension | Check tension and adjust | |
| Worn sheaves | Replace sheaves | |
| Debris in sheaves | Clean sheaves > Improve Shielding > Remove dust, paint, dirt and debris from the grooves |
Unusual Vibration in the Drive Belt
| Symptoms | Probable Cause | Corrective Action |
| Belts Flopping | Loose belts (under tensioned) | Re-tension |
| Mismatched Belts | Install a new matched set of belts | |
| Pulley Misalignment | Align the pulleys | |
| Unusual or Excessive Vibration | Incorrect Belt | Use correct belt cross section in the pulley > Use correct tooth profile and pitch in the sprocket |
| Poor machine or equipment design and setup | Check structure and brackets for adequate strength of the machinery | |
| Pulley out of round | Replace with non-defective pulley | |
| Loose drive components | Check machine components and guards, motor mounts, motor pads, bushings brackets and framework for stability, adequate design strength, proper installation and proper maintenance. |
Problems with Sheaves
| Symptoms | Probable Cause | Corrective Action |
| Broken or Damaged Sheave | Incorrect sheave installation | Do not tighten the bushing bolts beyond the recommended torque values |
| Foreign objects falling into the drive | Use an adequate drive guard | |
| Excessive Rim Speeds | Keep the pulley rim speeds below the maximum recommended values | |
| Incorrect belt installation | Do no Pry belts onto pulleys | |
| Severe Groove Wear | Excessive Belt Tension | Re-tension and check drive design |
| Sand, debris or contamination occurred | Clean & Shield the drive as well as possible | |
| Wrong Belt | Make sure that the belt and sheave combination is correct |
Problems with other Drive Components
| Symptoms | Probable Cause | Corrective Action |
| Bent or Broken drive shaft | Extreme belt over tension | Re-tension |
| Overdesign of the drive | Check drive design > May need to use smaller or fewer belts | |
| Accidental Damage | Redesign the drive guards | |
| Machine design error | Check the machine design | |
| Accidental damage to guard or a poor guard design implemented | Repair or redesign for durability | |
| Pulley mounted too far away from the outboard bearing | Move the pulley closer to the bearing |
