I recently bought a clausing lathe with a 5 hp 2 speed 3 phase motor. I'd like to run it with a vfd and use the drum switch and on off lever to start/ stop and reverse it, a friend of mine told me this was not the safe way to go and that I should use only momentary switches for the control circuit of the vfd. I'm sure I saw a wiring diagram somewhere that showed maintained switches operating the lathe through a vfd. The only down side I can see is if you turn off the machine with the drum switch and later set it for forward or reverse without switching off the start / stop switch it would start up, maybe unexpectedly. So I think maybe the solution is to prevent it from being shut off by the drum switch which is doable if I'm remembering the schematic corectly. As far as the 2 speed motor is concerned I was thinking I'd use only the high speed. Any advise welcome and also recommendations for a 5hp vfd. Thanks oscer