two speed async motors check

[fab1961]

Dear all,

I would like to check on site whether an old 2-speed async motor has two separate windings or a Dahlander winding. Chances are for Dahlander, since the speed ratio is 1:2, only horsepower does not fit since it is labeled 3.5/6 kW.
If I disconnect cables and measure the resistance between one terminal of group 1 and any other of group 2, if it is two separate windings I should read at least some kiloohms -am I right?

Thank you very much.

 

[LionelHutz]

Check the number of contactors. 2 contactors is 2-winding and 3 contactors is 1-winding.

But you are right, the 2-winding motor should have 2 windings with a decently high impedance so you should see a high resistance between the different windings. A 1-winding motor will have low to almost shorted impedance between all the terminals.

 

[edison123]

Use a DMM or 24 V lamp test to check for continuity between the six leads. If all the six leads have continuity, it's a dahlander winding. If only two sets of 3 leads have continuity, then they are 2 different windings. Most likely it's a dahlander.