How to choose matching motors for transmission equipment
Hengli Motor's after-sales service representative, Xiao Wang, recently dealt with a broken shaft of a motor, which occurred at the root of the shaft extension. Based on years of experience accumulation, it is preliminarily analyzed that the customer's operating conditions are quite special, and it is likely that they are using pulleys for dragging. Judging from the on-site situation, it is consistent with the previous prediction. The motor is a 6-pole motor with a center height of 315 and a power of 90 kW. The customer used a pulley to drive the crusher. The instruction manual of Hengli Motor has indicated that customers are not allowed to use belt transmission, especially for dragging crushing equipment.
Regarding how to choose a matching motor for transmission equipment, Hengli Motor has officially announced the issue of using belt transmission for motors. We hope that users can pay attention to:
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.
In addition, if the motor is not concentric with the dragged equipment, the motor shaft will bear additional or unexpected alternating loads, which can cause metal fatigue damage to the motor shaft during operation. When the additional load borne by the motor shaft extension end or the relatively weak link of the shaft is too large, it will cause the motor shaft to bend and deform in the radial direction. What is even more frightening is that this will further deteriorate the operating conditions of the motor shaft, and the combined effect of the load and torque will eventually cause the motor shaft to break, usually near the bearing, mostly on the inner side of the end cover.
