Step-by-Step Industrial Belt Drive Maintenance
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:
- 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.
- 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.
- 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.
- 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.
- 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.
- Check bushings/sheaves – Ensure proper installation was complete as incorrect bushing installation can result in sheave misalignment as well.
- 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.
- 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.