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Need Help With My Scrapheap Rpc Build

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jhuston

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Hello everyone,

I have eleven three phase machines in my shop that would love to help me get work done, but are sitting idle ( some of them for years) because I've never gotten around to building a rotary phase converter.
Well, now's the time.
I've started collecting parts to build an RPC. I have a 5hp, 1725 RPM 3 phase motor ( 14A @220) and a Furnas size 1 mag starter with fused disconnect. I'm a mechanic by trade, and while I have little problem repairing the used equipment that comprises my shop ( thirty-one vintage machines, the newest built in the late 1950's, the earliest sometime before 1903), I'm a little intimidated with drawing up a wiring diagram for an RPC; I just don't "get" electrical concepts the way I understand mechanical ones.

I understand the basics of how an RPC works, but the finer points ( start versus run capacitor layout, etc.) are confusing to me. I don't expect someone to do it for me, but I'll be the first to admit I need whatever help I can get.

Thank you,
-James Huston, out of his depth
 

jhuston

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Thank you for the diagram; I'll post my progress ( and probably bug you for more help!)
James Huston
 

jhuston

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I'm currently figuring out my wall mount for the RPC . Originally I thought I'd need to incorporate a donkey motor to spool up the 5hp idler, but if I can do it with capacitors, that makes it a smaller package.
-James Huston
 

Ulma Doctor

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i wanted my design to be as compact as possible.
there is no need for a motor to start the idler.
just be careful when you are handling capacitors, treat them like they are rattlesnakes
 

jhuston

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Point taken. I've never been bitten by a capacitor in my years of rebuilding motors, and I certainly don't intend to get zapped now!

-James Huston
 

jhuston

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Well, it's been a long time since I've been able to give the RPC build my attention; I've been doing motor rebuilds and power tool restorations to bring in more money, and haven't had a moment to myself to work on this. I've made some progress, but I have yet to size or install the capacitor to the one leg of the 3 phase motor. If my pony motor is 5 hp, 14 amp 1725 rpm, my capacitor should be about 200 uf, shouldn't it?

-James Huston
 
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