Has anyone had experience with connecting a 20 HP 480 volt 3 phase motor that is controlled by a VFD to a GFI circuit breaker? We are working on a new brewery. The electrical engineer specified a 480 volt cord drop for the owner to plug in a transfer pump. The owner wants us to mount a VFD on his portable motor cart. I am concerned that the VFD will cause the GFI breaker to trip. My local motor shop told me there is built in ground fault protection in the VFD.
VFDs designed for the US marketplace and UL listed as "Motor Controllers" (as opposed to some of the bottom feeders who list them, but as "Power Conversion Equipment), are now required to provide the Motor Short Circuit and Ground Fault protection. But that is only for down stream of the VFD, not the supply side.
Also, this is NOT intended to be "personnel protection" GF, aka "Class A Ground Fault" if that was the intent of the requirement, it is "equipment" protection, or "GFPE". Most likely that was the case for your 480V breaker anyway, so if that's the case, the VFD will be doing the same thing.
Most likely there will be common mode noise associated with a VFD on a portable cart because it's hard to provide proper grounding, so it's likely to create nuisance tripping situations on a breaker with GF trips.