The reasons for the large no-load current of the motor are as follows:

　　1. The number of turns of stator winding is less than the normal value.

　　2. Large air gap between stator and rotor.

　　3, the iron core silicon steel sheet quality is poor (factory unqualified products or use fire method to remove the winding will burn the iron core).

　　4. Insufficient iron core length or insufficient effective length due to improper stacking.

　　5. The insulation layer of the iron core silicon steel sheet is crushed or the insulation performance of the original insulation layer fails to meet the requirements due to the excessive pressure during the superposition.

　　6, winding wiring error. If the three-phase star connection is three-phase Angle connection, the no-load current is more than 3 times of the normal value, and the number of parallel branches is more than the design value.

　　7. The motor with the rated frequency of 60Hz enters the ac point of 50Hz, at which time the no-load current will be more than 1.2 times the normal value.

　　8, the power supply voltage is higher than the rated value, in the rated voltage annex, the no-load current and voltage square (or even 3 power above) is proportional to, so the increase of no-load current will be far more than the increase of voltage.