Ok. I'll go first..

[murphy625]

Here is a photo of mine...

220VAC 1PH input
220VAC 3ph output and that goes into a 30KW 480V 3Ph step up transformer.
All painted ugly gray.

Total cost to build ~$600

Murphy

[CNCadmin]

How does that whole thing work exactly?

[Al_The_Man]

Originally Posted by CNCadmin How does that whole thing work exactly?

Takes 240 single phase and uses a 3ph motor to produce a 3ph supply.
I posted some links in an earlier thread that links to some design criteria and a schematic of a rotary converter I built a while ago http://cnczone.com/forums/showthread...tary+converter
The link point to the metalworking.com drop box where I got the original design.
Al.

[murphy625]

I feed 240Volts 1ph @ ~60amps. A capacitor helps get the 3ph motor turning. (gets to full speed in less than 1/2 second just like it was powered by normal 3 phase current). Since the motor has 3 phase windings, and is running without load, the 3rd phase is induced. (like a virtual fake) but it will carry current. This output goes into a transformer with a 480 volt primary and 220 volt secondary. (i have it hooked up backwards if you consider there is such a thing in a transformer). My 220volt input gets boosted to 480 volts.. I trade amps so even though the 220v is going in at a max of ~60 amps, the 480volt side is fused at 25 amps. (no getting away from Ohms law)

What is great about it is that a 10 ga wire will run a 10hp motor and still have plenty of capacity left to spare.
The bad news is that a 15hp motor means you either put it outside, or turn up the radio if your shop allows one! LOL

Murphy