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Hydraulic pump kicks out during operation - CNC


The problem I encountered on this job was a strange one. The Hydraulic pump would basically alarm out and go blank then completely restart. During this occurrence the machine would sometimes alarm out with low hydraulic pressure alarm. But given that the alarm circuit is usually on a timer before the alarm is issued also made the symptom not repeat as the hydraulic pump would restart very quickly.
Considering that the pump only had three phase wires going to it and no alarm circuit I figured it must have something to do with either ground noise or the three phase power. The alarm on the display was pretty generic and not much help. Tried monitoring the power but seen no change in any of the 3 phase legs. Changed the ground connection to another ground rod and checked for stray voltage. Decided to change the contactor since it’s the only thing that controls the three phase to the Pump, figured it could possible be single phasing.
Finally after troubleshooting this intermittent problem for several hours I was finally able to isolate the problem to the spindle being in high gear and using the high windings. So could it be the drive? Probably not. I decided to start looking at the wires for the spindle motor, what I end up finding was that one of the wires was worn through in the J box. Vibration from the machine was enough to wear a whole in the insulation.
After wrapping it up with Rubber Tape problems disappeared. I also strapped down all the wires to keep from occurring again.