Are you hearing a slapping noise? This can be caused by poor tension, which may cause a reduction in performance and lead to belt breakage.
On the Run Inspection-
Use a stroboscope
o Check if there is any damage on the belt, cogs may be damaged.
o Check if the belt is properly tensioned. Look for excessive sag on the slack side of the belt when it is under heavy load. If the sag is excessive, tensioning is needed.
The full standard can be found in IDCON’s Condition Monitoring Standards Volume 3.