6 lead motor identification

[Martin300]

I'm trying to hook up a 600V, 200HP 3 phase squirrel cage motor. It had six leads with no identification tags. It's 4 pole at 60 Hz. It drives a fan so reverse rotation for a short time is not a problem.

I can identify the individual winding pairs. We're using it in Delta with across the line starting. If I get one winding backwards compared to the other two (opposite magnetic field) will the motor still run? My thinking is that it will fail to rotate and draw something approaching locked rotor current.

Is there a way of testing to find the polarity of the windings- i.e. inject a small AC current into one winding and measure the phase relationship on the other windings.

I've looked through the forums and my old textbooks but didn't find any answers. Perhaps I'm out-thinking myself, just hook it up and try it out. Thanks for any advice you can offer.

 

[petronila]

Hello Martin,

This could help you:

a. Random three wires and Asign arbitrary numbers from 1 to 3
b. Check the continuity between the no marked and marked wires: Continuity with 1 is marked like 4, continuity with
2 is marked like 5 and continuity with 3 is marked with 6.
c. You could use the surge tester, and find the lead combination that gives the correct pattern (1-6, 2-4, 3-5).
d. Check Insulation and start the motor.

Regards

Petronila

 

[petronila]

Martin,

The Thread 237-153197 have some procedures for It using a Metter and one Batery.

Regards

Petronila

 

[Martin300]

Thanks Petronila

The thread did have usefull info, especially the post by wiretwister. The battery and meter method is easy to use.

I should of found that post myself but didn't use the proper keywords in my search. Thanks for your memeory or searching skills.

It was a nasty place to work, 30km/h wind at -10C. The wind keeps the fan rolling over even with the motor disconnected and the fan beside it is so noisy you can't get a good sense of how the motor is starting by the sound.

I'll bet they mark the leads before they take it apart next time.

 

[place1234]

Using a Megaohm meter and AC should solve your problem.

 

[place1234]

Using a Megaohm meter and LV AC supply to motor should solve your problem.