I want to try and run a 10" standard modern utilathe with a 230v 3 phase motor rated for 2.5 amps using a vfd off a 120v single phase outlet. Have never ran a vfd before.
Is this possible?
Is it a good idea?
My other machines are hard wired in but would like to use a vfd on this machine for fine speed control. My reasoning is if I'm getting a vfd anyway why not use it off the existing outlet that's located right behind the machine and save some money by not having a electrician coming out.
It is an excellent idea... first, the lathe spindle is IMO the ULTIMATE application for a VFD in a workshop... and the second, doing so allows you to pick up good stuff, cheap, and make it work.
I've got several machines that deal with same circumstance, but they're 480v/3ph, and my supply is 240v/1ph... and their motors are in the 3-15hp range... but what I do will work fine for you...
Get a dry transformer that's indicated as having a primary connection option of 240v, and a secondary of 120v... and about 2.4kva. Wire it backwards to your 120 supply (through a proper contactor or double-pole switch, for safety). The primary winding will then present 240v single phase, which you can connect to two of the three line connections (i.e. L1 and L3) of your VFD.
You'll need to use a VFD that either allows single-phase in, or can be set to disable phase loss protection. I use old surplus drives that some guys sneer at, because they're very inexpensive and well proven...
But something you might consider- IF you want to go this route, check your machine, see if that spindle motor will run at 480v.
Why?
Because EVERYBODY wants a 0.5-3hp 240v VFD... but NOBODY wants a 0.5-3hp 480v VFD. You can use a 480-240/120 transformer to provide 480 single to a dirt-cheap surplus VFD and run that spindle just dandy.