1. Overheating when the motor is no-load:
（1）error of stator winding connection (for example: connecting a star into a triangular connection).
Treatment: check the connection mode.
（2）The voltage of the power supply is too high.
Processing method: check the main power supply voltage and no-load current.
（3）It can not be cooled because of the moral clogging of ventilation.
Treatment method: eliminate ventilation duct ventilation barrier.
（4）the rotating direction of the fan is wrong (designed as a single rotation motor).
Treatment: check the fan and the direction of rotation.
2. Overheating when the motor is loaded.
（1）The motor is overloaded.
Treatment methods: check current, proper load reduction.
（2）The voltage is too high or too low.
Treatment: check the voltage.
（3）The motor runs in one way.
Treatment method: investigate and deal with the disconnecting place of the line.
（4）fixed rotor phase wipe, water flow shortage of cooler or local blocking.
Treatment: check air gap, adjust water pressure, water and exhaust.
3. stator local overheating
Cause: stator interturn short circuit (some coils are overheated, and have buzz).
Processing method: find out the short circuit winding for processing.