How to judge and repair the single-phase motor?

Update:15 Jun 2020
Summary:

  Single-phase motor failure phenomenon: no rotati […]

 

Single-phase motor failure phenomenon: no rotation after power-on check: The motor winding has three taps. Use a multimeter to measure the resistance between any two. It is found that one of them (red) is disconnected from the other two.

Cause of failure: The analysis may be that the winding is burnt out.

At this point, the simple maintenance method is to directly replace the motor. However, after turning on the motor, it was found that the manufacturer embedded a thermistor in series with the winding at the end of the winding, and the thermistor was closely attached to the outside of the winding. It is found that measuring the thermistor does not work, and directly measuring the winding is working. It is concluded from this that the winding is not energized due to the damage of the thermistor resistance, and the winding is not burned out.

Solution: replace the thermal protection resistor of the same model. After installation, power on and the motor runs normally.

Note: When disassembling and assembling the motor, and changing the thermistor protection of the winding, pay attention to the process to avoid damage to the motor. Experience: It is usually found that the motor is damaged and the motor is replaced directly. The method is simple and time-saving, but the component cost is high. Turn on the motor to check, you can further find the fault point, and targeted maintenance, although time-consuming, but the cost of components is low.