I would hedge a bet that you need at least a 3HP 3PH rotary converter.
I'm not an electrician, though. This is based on my experience as I mentioned above.
How many wires are coming out of the motor?
Did you get bearings for the upper and lower guides yet?
Do the wheels spin true?
How is the drive-train?
I would work backwards from there. You can always swap in a single-phase motor if you don't have other three-phase equipment.