View Full Version : 200v Three phase motor 4 poles

04-08-2011, 05:27 PM
I'm getting 0 ohm from the windings no matter how i measure.

PE with U or V or W terminals
between the terminals U, V and W

Is this the right way to check? If it is, will this mean motor is gone?

thanks in advance

04-08-2011, 05:59 PM
It sounds like you have a ground on the motor, do you have the motor disconnected before measuring?

04-08-2011, 06:11 PM
yes, the motor is disconnected.
just re-measured again between PE with U or V or W terminals = open cct

between the terminals U, V and W = 0

04-08-2011, 06:35 PM
The winding resistance of a typical 3 phase motor is not going to read alot above 0 ohms.
There is not alot of point in measuring resistance, it would be more of a concern if you read an open.
What is the problem you are having?

04-08-2011, 06:38 PM
the problem right now is that the motor is not moving smoothly. kind of jerking move(move, stop, move, stop). that's why I'm guessing one of the winding got short.
Motor is controlled by a adjustable speed control. Forward and reverse works, but speed does not change.

04-08-2011, 08:10 PM
What kind of motor and controller? is this a AC servo motor, when you stated 200v 3 phase motor in your original post I took it it was a standard induction motor?

04-11-2011, 11:54 AM
Motor: Fanuc model 3 AC spindle motor 3 phases 4 poles
Controller: Leeson AC speed controller

04-11-2011, 12:33 PM
Sounds like it could be the controller?
I would get the motor tested on straight 3 phase to see how it behaves and take current reading of each phase.

04-11-2011, 06:59 PM
you mean connect the motor straight to 3 phase line and measure current between the line and motor? or between the windings?

If the controller is the problem, you mean the settings on it? or the actual controller?

I kind of suspect the terminals on the motor might be mislabeled. what is the way to identify which one is U, V or W terminal on the motor?

04-11-2011, 08:03 PM
Connect to 3 phase 200v and measure the current on each phase.
Should not matter between UVW, just that the motor will turn in opposite direction.
This is providing it is a standard induction motor, which it most likely is.