1、View appearance：The motor surface paint layer should be smooth，signs were complete；Enclosed type motor seat should be intact，and accessories complete.

2、Manual rotation：Turn the shaft by hand,The rotation should be very flexible, the momentum is good, there is no axial momentum.

3、Diagnostic bearing：The motor electrify fifteen minutes to twenty-five minutes，The bearings should be smooth and no stagnation phenomenon, and temperature is not high, there is no leakage phenomenon；

4、Check wiring：Open the junction box to see whether the phase line signs are clear and complete，Contact sheet whether of the compaction，and Nut whether of the complete.

5、Measure resistance：Use the rated voltage 500V to megger of the manual type，Measure the insulation resistance between the line terminal line and phase line of the line and  engine base，The insulation resistance of normal motor should be greater than one trillion。

6、Current measurement:When the motor is runing, measurement of the current of the motor is unloaded by a clamp type ammeter，Three phase current in any phase and the average value of the deviation shall not be greater than 10% of the average, the no-load current is generally rated current of 25-50%.