Motor Control Centers FV Staters and replacing with VFDs

[fso001]

Have a MCC located in an administration building on campus. It has full voltage starters in it. A couple decades ago, VFDs were installed inline with the motor starters. We had a VFD fail recently that fed one the air handlers. I want to develop a standard here so that we don't have the issues like this frequently. I feel fairly certain that the control system was not altered that controls the FV starter. I know for a fact that the fire alarm wiring to this FV starter is still intact. Basically I should disconnect all control wiring and remove the starter in the MCC can. Demo control wiring and fire alarm wiring. Connect the MCC fuses directly to the feeders going to the drive. There happens to be a disconnect near the drive and motor. Install new fire alarm wiring to the VFDs directly. Is this strategy comprehensive?

On a much more severe situation, one of the MCC cans feeding an air handler had its fuses and disconnect switch removed and replaced with a circuit breaker. They then took a small sheet of metal and screwed it to the can door to cover the hole left from removing the disconnect switch. Now you can open the door with everything energized. The MCC is about 40 years old so parts are probably not available. Is there a good solution for this issue after I remove the FV Stater?

 

[Johnnybob]

I don't think the door latch is an issue, with a circuit breaker, as all the terminations should be pretty well touch-protected.
As for the starters, you don't need them for the VFD feed, unless you want to use the existing control circuit, and even with the starter removed, you'll still need the disco to close the switch to the fuses. Most VFDs have several multi-use digital output relays built in.