Motor question

[lou4062]

Hi all. I do not have a particular problem with any of our appliances as I type this. However, I did have a question reguarding the testing of an appliance motor or compressor. I was wondering if measuring the ohms in the start and run windings of a suspect motor is a "true" test to find out if it is good or bad. I have taken one out of an older washer and was curious. I do not have an amp meter. I was wondering if the motor hummed, or cut off on its overload, etc., if that would show up in a windings test?


Thank you,
Jay

[LazyPup]

You can test the windings with an ohm meter but that will only confirm the condition of the windings themselves. In order to test the bearings , or in the case of a compressor, to test the valves by electrical means you need to have the unit running and take amperage tests and compare the results to the rated load of the motor.

[lou4062]

Thank you for the quick reply LazyPup. It makes sense that a simple windings test is not all that can go wrong with a motor. Thank you once again.


Jay

[Phelps]

I'll just add that one can presume if the needle goes way over to the right, on an ohms test, that the motor is good? But it MAY indicate a dead short, as well! On a/c motors, you do not want any continuity between the lead wire going into the motor and the housing of the motor itself. Always check for that.

Also, the bigger the motor... the more resistance you are going to find. But, for the most part, the ohms needle will go MOST of the way to the right, on the meter...but not ALL the away. Be sure you 0-out the meter first before testing.