Motor Starter Feeding a VFD

As I understand your situation in the other forum you posted this in (too coincidental that it is a 75HP IR compressor on a VFD), you are having troubles with the VFD tripping out on UV when the incoming voltage dips too low and it requires manual reset, which causes lengthy downtime which costs more than the entire compressor.

Adding any kind of switching device ahead of the VFD will only serve to shift the problem to another area, namely the VFD failure. Repeated cycling of line power to a VFD stresses the DC bus smoothing capacitors, and/or a pre-charge resistor (if designed that way).

I was unaware that IR was making VFDs, and as it turns out they are not. This appears to be a brand-label of a Danfoss drive, likely a VLT because IR's Trane business unit brand labels that same VFD for HVAC applications. I have an older VLT 3500 manual here and although the fault codes don't go to 16, it does have an under voltage alarm separate from a UV trip. With that feature, you should be able to get some warning that would allow an orderly shutdown of the drive prior to the trip that has to be manually reset.

And by the way, on this older one it appears as though the requirement for manual reset itself is programmable, so you may be able to program it for automatic reset with a number of reset attempts.

Get some help from the IR people, this shouldn't be so difficult to work around but don't start throwing hardware at it that creates new problems until you have exhausted all other avenues.