• Schematic

Building a Rotary Phase Converter

This page describes how I built one of my Rotary Phase Converters.

While most pages describe using a potential relay from Graingers I found them to be expensive compared to a local electrical supply house.

I started with a used but good 15hp 3-phase motor. If the bearings and windings are good your off to a good start.

You need a few things to build the self starting rotary phase converter.

• Potential Relay pick up volts 165-180
• 15k 2watt Resistor
• 3 phase Contactor
• 2 Start Capiciators 400-480UF 220-250vac
• A n/o Start contact and a n/c Stop contact
• 4 Run Capicators 60UF 440vac

To get the voltage between the generated leg and the real legs with a load it required about 3 times as much capiciators between L2 and L3 as between L1 and L2. I don't have a clue why but with any kind of load at all the volts are within a couple between any two legs. Without a load the generated leg will be quite a bit higher but you never run it without some kind of load so that means nothing.

A remote start stop can be rigged up using low voltage buttons and relay.