As one who installs VFDs and programs them and also has worked some with rotary converters and has days operating generation and distribution.
1. If you need 3 phase from single phase for multiple tooling then rotary converter may be best option - especially if you want hard wired ie conduit etc and do not want to fool around with plug and unplug. Make sure converter has more capacity than all loads you intend to run simultaneous. Add a little extra capacitiy if you have hard starter ie air compressor.
2. you can run multiple motors off one vfd but ideally they should all be the same size.
3. NEVER BREAK the output of a running VFD. Turn them off with either the panel control or a hard wired stop.
4. If it has the capacity you could use one VFD to run multiple tools but you are back to plug and unplug or complicated switching. Do #1.
5. On machine tooling I would select speed and feed using gearbox and then fine tune speed with VFD
6. IF you run motor at very low speed ie 10Hz or less have additional cooling fan. Motor fan is running too slow to cool motor and you will burn it out.
dan Bentler
