Powerflex 525 Fault code F013 ground fault

At my work, a coil of plastic tubing goes over retracted circular fingers. A Poweflex 525 drives a motor to extend the fingers open to hold the coil, to be shrink wrapped. But only when it's time to retract the fingers, the 525 faults with the code; "F013 Ground Fault."

Before I look at the motor wiring, I wanted to get some opinions as to why the vfd faults only in one direction?

I just checked the voltage at u, v, w terminals to ground, and they were all 2.3volts (I did not reset the fault). If there really was a grnd fault, would I not get 0V on at least one of the three terminals?

There's a known anomaly with ground faults on 230V 3PH Frame A or B PF525 drives manufactured before Aug 1 2013. If your drive fits this description you might want to check the drives manufactured date. I assume from the article that this is an inherent problem and most likely the drive, or a part therein will have to be replaced.

562950 - PowerFlex 525 3 Phase 230V AC: Having an intermittently F013 Ground Fault
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Regards,
George