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My Oliver rotary phase converter

Fay & Egan 12 Model 316 12 inch jointer

Oliver Machinery Co. Model 232 14 inch tablesaw

DeWalt 14 inch GA radial arm saw

Oliver Machinery Co. Model 91-D hollow chisel mortiser

Oliver Machinery Co. 15 inch disk sander

DeWalt 14 inch GA radial arm saw

Powermatic PM100 12 inch surface planer

Yates-American J18 18 inch surface planer

Yates-American J145 Oscillating Spindle Sander

Oliver Rotary Phase Converter

Neither this site nor anyone at C.M. Oliver intend for this to be a handbook or guidance for building a rotary phase converter. This is only a journal of my process accompanied with photos. If you would like to build your own rotary phase converter, please consult you local electrician or motor repair shop. Continue reading at your own risk.

I have purchased several machines now that have 3 phase motors. Like many, I can neither afford to have 3 phase service run to my shop nor pay for it if it were installed. I have looked around for a rotary phase converter (RPC) for about a year now and have not found any in my price range.

C.M. Oliver Rotary Phase Converter

February 2006
Well, I finally broke down a purchased a converter. I did not buy the whole thing though. I found a guy in North Carolina who buys the parts needed in large quantities and was willing to build one for me. He put together a converter panel to go with the Westinghouse 7.5 h.p. motor mentioned below. My end of the deal was that I had to mount and wire the panel.

I built a small base out of two 3/4" thick pieces of scrap plywood sandwiched together and edged them with some sycamore pieces I had in the scrap bin. I bought some cheap casters to roll this thing around a bit when cleaning.

I mounted the motor to the base first, using some 3/8" lag bolts. Then I mounted the panel to base using some 1.25" drywall screws. I ran the motor wires (three of them) into the panel through some flexible conduit and a hole I had drilled. I then connected all of the wiring according to the schematic. What this means is I hooked up the motor wire where I was told to, ran power from a single phase disconnect and connected them where I was told to, and ran a wire through flexible conduit out to some 3 phase outlets and connected them where I was told to.

This all took some time and a few extra bucks for the wheels, conduit and 10 gauge wire, but it starts my tools like a dream. I was using a Ronk Add-A-Phase, a static converter, and it ran my saw ok, but the RPC starts it in less than half the time and I can run any of my other machines, smaller h.p. to larger h.p. on the same RPC. The static converter is set up for only a specific h.p..

Oliver RPC Hooked up.

I do intend to get some voltage meters and explore the load balancing techniques that are talked about on several groups. For now, I'm just happy this all worked out to be so cheap and useful.

Parts acquired:

Part Description Price

Westinghouse 7.5 h.p. 3 ph. motor
Westinghouse 7.5 h.p. 3 phase motor
I got this motor with my Fay & Egan jointer, purchased at auction. I went with a single phase motor for the jointer, so this motor was surplus to me.


Panel with capacitors, etc.


25' flexible 3/4" conduit


4 - 4" rubber casters


25' - 10 gauge copper wire (4 individually insulated and sheathed wires)


2 - 4" boxes and plates to hold outlets