What you need depends on what you’re trying to run, and what you’re
trying to do with it.
There are a couple of different options, depending on application.
(A) rotary converters. Expensive, but best for things where you need
’real’ 3 phase, and you have a machine that’s more than just a
(B) static converters. Cheap, but the legs aren’t usually perfectly
balanced, and not quite as high rated as a rotary. Good for things
like sanders, or blower motors
© VFD’s. (Variable Frequency Drive) A modification of a static
converter, these will take a 3Ph motor, and make it infinitely
variable. You lose some torque on the low end, and it will play hell
with anything other than a motor, but can be very useful indeed
for motor only setups.
Size depends on startup currents. There are ‘hard starting’ things
like lathes and air compressors, versus ‘easy starting’ things like
belt sanders. What you have selects what you need. That’s where you
need to talk to the engineers at whatever company you end up going
with for whatever product. They’ll know best what you need.
I’ve had good luck with Temco, that’s the place where I got the
rotary that runs my big lathe. That’s got a 5HP motor in it, but
being a lathe, it needs a 7HP rotary to get it started.
For whatever that all was worth.