I am working on a DIY Rotary Phase converter with pony motor. This will use single phase 240v and run capacitors to feed 2 legs of a 3 phase motor, which will generate the 3rd leg.
It uses a 1/2 HP 120v motor (pony motor, starter motor) to start a 5 HP 3 phase motor. I would like auto-start and cutout, so the idler and starter are never energized separately and the starter cuts out after the idler spins up.
The approximate design is below. A 120v switch turns on the starter motor and a 2 pole relay to power L1 and L2 of the idler. The idler has run capacitors between L1-L3 and L2-L3. When the idler starts, L3 will energize the cutout relay (240v NC), which turns off the starter motor. L1, L2, and L3 would be used to drive a 3 phase load.
I used ground symbol for neutral in the schematic.
My primary concern is with the cutout relay wired in parallel with the load on L3. Will this cause problems? If so is there an easy modification I can make to the circuit? Will the cut out relay energize prematurely due to the run capacitors?
Information regarding rotary phase converters: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html http://www.paragoncode.com/shop/rotary_converter/
Final simplified design:
The circuit diagram tool doesn't have an option for aux contactors or 3 pole relays, so RLY AUX indicates a 3rd pole or an AUX connection on the contactor