We have an old Niigata CNC Vertical Machine with a Fanuc 11m control and Fanuc circuitry.
We were getting an alarm that according to Fanuc was very generic but a Tech traced it to being a problem with the brake on the Z axis motor. We were popping a certain brake that suggested this. We were able to get it running by bypassing a breaker but Z didn't last long it sounded like the brake was holding up and soon the Z-axis board was giving us an OVC alarm.
So we contacted a company who rebuilds motors and had a re-serviced motor set to us.
We hooked the motor up and all the wiring is now proper not by-passing anything and the machine comes up fine.
The Brake issue seems to be solved but when we try and move -Z- we get an alarm on the drive board once again OVC and the machine alarms out.
We unhooked the motor from the Z-axis ball screw and it runs fine with out a load? We have the machine blocked very low in the Z axis and are wondering if that is perhaps causing it to bind or is it simply just a bad motor?
We are also wondering if there is any gain adjustments we could make on the Drive Board to compensate for the OVC error?
Any suggestions would be much appreciated!!!
Send a P/M to Dan Fritz on this M/B. He has tremendous insight into Fanuc's