Example of belt drive shaft breakage

 The problem of using belt transmission for the motor 

For motors connected by pulleys, when some customers equip the motor output shaft with pulleys, if the pulleys are too heavy or the belt is installed too tightly, it can also cause the motor output shaft to experience continuous alternating bending stress during operation. This stress produces the maximum bending moment on the shaft near the output shaft bearing fulcrum, causing fatigue due to repeated impact, gradually cracking the shaft, and ultimately complete fracture. 

In general, large motors should avoid using pulley transmission as much as possible. The technical conditions and specifications of the motor are specified in the manufacturer's manual. For motors with H280 and above, it is not recommended to use belt pulley transmission. The reason or theoretical basis is as mentioned earlier: belt transmission itself causes the motor shaft to bear normal loads while also adding bending stress. In addition, the belt is too tight, resulting in the motor body always bearing large alternating loads during operation. The stress concentration problem in the shaft extension and bearing parts is the most serious, which can easily lead to shaft failure.