Powerflex 525 F005 - Frayed cable?

Thought I'd share a problem I encountered last week..

Maintenance called to say they were receiving a recurring fault on a VFD that controls a short conveyor belt. F005, which indicated OVERVOLTAGE. I arrived on-site an hour later without all my tools, so I did what O could with my multimeter.

Input voltage was 576V (575V nominal, so that wasn't the problem). None of the eleven other VFDs in the cabinet were reporting errors

Rang out motor leads at the connection box and got within 1 Ohm of resistance between the three leads

Reconnected the cable at the motor connection box, disconnected at the VFD, rung out each lead and returned similar resistance reading

Programmed and installed a replacement VFD, powered it up and it returned the same error!

Eventually found a chafe in the cable between VFD and motor, about 4' from the motor, buried in a cable tray!

This is a first for me - any time I saw F005 it was caused by having insufficient deceleration time, a faulty brake or a payload continuing to move due to inertia

I should mention that I did not have a Megger with me. There was no obvious insulation deterioration - the chafe only affected a portion of the outer braided shield

I can't really see how that gave you an over voltage fault. from my understanding, over voltage is measured on the DC bus. As you said, regenerative voltage is often the culprit. Sometimes you'll get it from excessive Ripple, from bus capacitors that are going bad. Not sure I can wrap my head around how a cable issue caused the fault.

It's likely due to what's called a "DC Bus Pump Up - Boost Converter Phenomenon" as described in KB article # 864938. The compromised cable was exacerbating the Common Mode noise getting into the system and back into the VFD DC bus.