Reason:
1. Tooth skipping.
2. Accidents such as burning and melting of bearings of passive wheels.
Countermeasures:
1. a: Overload.
B: Initial tension is insufficient.
C: The number of meshing teeth is too small.
D: The bearing is not rigid enough.
2. a: Check the design.
B: Excessive tension adjustment.
C: Increase the diameter of pulley and the number of meshing teeth.
D: Exchange bearings. Increase bearing rigidity and firm fixation.