Belt drives are the most cost effective, reliable means of shaft-to-shaft power transmission speed change but they require regular inspection to ensure proper performance. Follow these steps for best practices on belt drive installation and inspection:

1. Check temps – Check the ambient temperature of the belt itself with a temperature gun (preferably while still operating). V-belts should not be run above 140°F (60°C) and synchronous belts should not run higher than 185°F (85°C). For every 18°F (10°C) increase in belt temperature – which is a 36°F (20°C) ambient temperature change – belt life is cut in half.
2. Shut down the system – Given the nature and size of these machines, typically a complete shutdown is necessary as is a number of other precautions like tagging the machine and locking machine power in the off position so others are aware and testing it to ensure it’s safe for inspection.
3. Inspect the belt – Remove the safety guard and mark a line on the belt. Work your way around it, looking for cracks, frayed spots, cuts, missing teeth and unusual wear.
4. Replace belt if needed – If a belt needs replacing, never pry it on or off a drive, always loosen the take-up bolts and move the sheaves to create slack. Only use new belts from the same manufacturer on one drive. Never mix and match belts from different manufacturers.
5. Check drive alignment – Using a straight edge, string or laser alignment tool, check positioning. There should be 4 points of contact across the drive if it is properly aligned. The larger the misalignment, the greater chance for belt instability, wear and V-belt turnover. V-belt drives should be aligned to within .5° or 1/10″ per foot of center distance span. Synchronous drives and poly-V drives should be aligned to within .25° or 1/16″ per foot of center distance span.
6. Check bushings/sheaves – Ensure proper installation was complete as incorrect bushing installation can result in sheave misalignment as well.
7. Measure tension – Using the Force/Deflection method and a tension tester, check the tension of the belt. V-belt drives should be tensioned as per the manufacturer’s recommended tension chart at the force rate specified. The deflection distance is to be 1/64″ per inch of span length. So if the span length is 32″, then the deflection distance should be 1/2″ (32/64″) to reach the specified force.
8. Doublecheck alignment and tension re-iteratively – If you change one then you must check the other until neither needs to be adjusted again. Under-tensioned V-belts will cause slip and excessive heat while under-tensioned synchronous belts will jump teeth and possibly snap in half. Over-tensioned V-belts and synchronous belts both cause reduced belt and bearing life due to excessive loads and tension.

If you have any questions about V-belt installation, contact Dayco’s US Industrial customer service team at 833-721-2355. Our team will put you in touch with the local Dayco Industrial sales agency serving your area to provide additional expertise if needed.