Motor Testing

[ej45]

How should a three phase motor be tested? The motor in question is a semi hermetic compressor, 460-60-3. The started is a star delta. The motor faults on high current draw. The screw compressor is locked up and pulling locked rotor amps. I disconnected the motor leads and dry ran the starter to check voltage and operation. My question is, with six motor leads T1, T2, T3, T4, T5, T6, how should the windings be checked with an ohm meter ( I wanted to confirm the windings were good). I did check for shorts and megged the motor.

[Rzn]

Dear ej45

 

I have also experienced such case. I want to explain what I did.

I connected an asynchronous motor at star delta starter whose leads were no identifications. When I started the motor, it draws too much current and MCCB tripped. I understood that there was a problem in justification of leads. So I checked the leads and marked them with U, V, W, X, Y, Z. Now I connected the leads as per my rough justification and first I run the motor on star. During that I had to remark the leads. When motor run on delta (running on star ok), MCCB gain tripped. Now I interchanged the leads from delta contactor one by one and run the motor ok.

You should do this way. Other wise, motor winding would be checked.