V-Belt Maintenance

V-Belt Maintenance is a requirement if you want to insure optimum belt drive performance. This process requires proper maintenance and discipline in order to insure effective belt operation and a long service life. When coupled with a regularly scheduled maintenance program, belt drives will run relatively trouble-free for a long time.

General Rules: (if you want to stop V-Belt failures)

1. Insure proper alignment of sheaves both parallel and angular using a sheave laser alignment tool. Do not use a straight edge or string if one expects optimal life from your V-Belts.

2. Use a span sonic tension meter to measure deflection and tension of a V-Belt.

 WARNING: Over-tension of belts is the number one cause of V-Belt Failure. 10% over-tension of V-Belts result in a reduction of bearing life by 10%.

3. Use Infrared for identifying over tension. Use vibration analysis for loose or damaged belts and strobe-lights for operator or maintenance craft inspections.

4. Upon installation, new belts should be checked for proper tension after 24 hours of operation using a strobe light or tachometer. Failure to execute this process on critical assets could result in V-Belts not meeting expectations of the end user.

5. Tighten all bolts using a torque wrench and proper torque specifications.

Failure Modes experienced on V-Belt Drives:

Tension Loss, Caused by:

o Weak support structure

o Lubricant on belts

o Excessive sheave wear

o Excessive load

Tensile Break, Caused by:

o Excessive shock load

o Sub-minimal diameter

Improper belt handling and storage prior to installation (crimping)

• Belts should be stored in a cool and dry environment with no direct sunlight. Ideally, less than 85˚ F and 70% relative humidity.

• V-belts may be stored by hanging on a wall rack if they are hung on a saddle or diameter at least as large as the minimum diameter sheave recommended for the belt cross sec-tion.

• When the belts are stored, they must not be bent to diameters smaller than the minimum recommended sheave diameter for that cross section. (see chart above)

• Belts may be stored up to six years if properly stored at temperatures less than 85˚F and relative humidity less than 70%.

• If the storage temperature is higher than 85˚ F, the storage limit for normal service performance is reduced by one half for each 15˚F increase in temperature. Belts should never be stored above 115˚F.

o Extreme sheave run-out

Belt Cracking, Caused by:

o Sub-minimal diameter 

o Extreme low temperature at start-up

o Extended exposure to chemicals or lubricants

Author- Ricky Smith CMRP