‍‍‍‍‍‍(one)Motor protectorThe human body surface should be kept clean. Too much dust and moisture can easily cause the overall grounding resistance of the protective device to decrease and cause faults.

(ii) Check whether the output and input terminals, contacts or connection software of the protection device are in good contact, whether there is overheating, air oxidation, electrode connection line damage due to poor contact, especially the overheating of the three-phase current main control circuit due to poor contact or improper cable diameter. 　

(3) Check whether the display of the motor protector indicator light, digital display tube and display screen is normal.

(IV) Check whether the motor protector and connector are firmly installed.

(V) Check whether the setting current of the motor protector has any changes or deviations from the original preset value, especially those using potentiometer knobs and dip switches to operate components, which are easily changed by random adjustments by the operating personnel and the original preset value.

(VI) Check whether the cooling and exhaust system of the motor is blocked, whether there is any abnormal noise during the operation of the motor, whether the insulation value is reduced, whether the DC contactor circuit breaker is damaged, whether there is noise when it is attracted, etc.

(VII) On-site inspection of the key functions of protective devices: After the protective device maintenance action, first observe, check, indicate or indicate whether it is appropriate, such as the common fault type, overcurrent value, motor thermal power status, etc.