It sounds like you might have a bad servo amp, or at least one that needs adjusting, What type of amps do you have? Also try swopping two drives over if they are all the same size.
There are a couple of ways to test the motor/tach/amplifier. Firstly, if you can easily disconnect the motor drive and with the power off, spin the shaft by hand and monitor the voltage on the tach leads and see if you get a +- voltage swing output polarity will depend on the direction of the rotation.
Secondly, disconnect the motor drive and the analogue input signal and if possible wire a 5k~10k pot accross a 9v battery to supply an input to the amp and see if it rotates ok.
I assume this is a mill that has been running ok up till now, or is this a new installation?
If you have older Westamp drives on it, they were prone to component aging problems, swop one out as above. If you post the kind of drive you have, I may be able to help with the setup.
Al
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CNC, Mechatronics Integration and Machine Design.
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E. |