Maintenance & PM's

A loose belt can slip and overheat. Excessive tension increases bearing loads and can shorten belt and bearing life. The aim is to achieve the manufacturer’s specified tension.

This procedure applies to conventional V-belts on an adjustable motor base. Always check the instructions for the particular fan and belt.

1. Isolate the equipment

Stop the fan, isolate and lock out the electrical supply, and verify the equipment is safe before removing guards. Allow the fan to stop completely and prevent airflow from other equipment turning it. A BMS stop command alone is not isolation.

2. Inspect the belts and pulleys

Check for cracking, fraying, glazing, contamination and worn pulley grooves. Check the motor mounting and fan bearings. On multiple-belt drives, replace worn belts as a suitable matched set. Release tension before fitting belts—never force them over a pulley.

I’m seeing a lot of sites lately just replacing belts.

If the pulleys are aligned properly and the tension is set right, belts should last a lot longer than what we’re seeing.

Before swapping belts, it’s worth checking alignment.

You can do this with a straight edge or a piece of string. I usually just use string . (Cheap, easy to carry, fits in the tool bag, and does the job.)

A (top left)