Re: [CAD_CAM_EDM_DRO] Re: Please help!!! I have run away servos on X and Y

I submit that you just have the motor polarity reversed. The stop and
go runaway suggests that the amps are working fine. The reason that
I say this is that there are 2 control loops -- one is around the tach and
the other is on the position. When the position and the tach polarity are
out of whack, they fight each other, thus the stop and go. If the motor
polarity is wrong, you get a straight runaway.
Eric

> Hi Roger,
>
> I have tested the tach voltage at the servo amp past any connectors
> that could be causing resistance or false readings. Everything checks
> out OK. I've even swaped polarity at the tach, the result was a run
> away that paused about every 3", kind of a stop and go run away. I've
> not tried swapping polarity of the motors, that was suggested in a
> couple of other replies.