# My RPC maze



## Fishchips (Oct 5, 2011)

I started with my first RPC build for a dual pump Ingersoll Rand air compressor. It was a 10 hp unit with a pony start motor. I sold that compressor and found a Champion 5 hp compressor that I currently have in my shop.

I added a 7.5 hp idler to the above idler to see if it would start a 10 hp motor, no problem. I upgraded the circuit to 6 ga wire on the 50 amp breaker. I've since added another 10 hp idler to the combo for 27.5 hp.

I plan to add a bigger circuit and wire because I have three 15 hp IR 3 cylinder compressors. I'd like to straighten up the wiring but I lease the building.

A friend gave me a pallet of three phase motors so I have a test disconnect for that.

The large panel is a three phase panel not installed yet.

I made a You Tube video of the madness, try not to laugh too much.

[video=youtube;ACEdOp-cRxI]http://www.youtube.com/watch?v=ACEdOp-cRxI[/video]


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## Fishchips (Oct 5, 2011)

Sorry about that. Rotary Phase Converter(RPC) Used to power three phase equipment on 240v single phase power. Variable frequency drives(VFD) are used in three hp and smaller equipment also. 

In a nut shell, I'm wiring a three phase motor(idler) to a 240v single phase circuit, spinning it to speed with a pony motor(gas motor) and applying 240v. This will start the three phase motor and I have three phase 240v power. The other idlers are wired in parallel and will self start.


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## Starlight Tools (Oct 5, 2011)

Ouch!

Just do not ever let the electrical inspector any where near your building! LOL

In its simplest form Dave H yes that is a RPC, but personally I prefer the ones that come with a stamp on them that say they are electrically approved for the country I live in. also they usualy have a capacitor bank on the drone motor to even out the third phase that is being generated.

Fishchips, I do hope that you at least have the input to that unit wired with Magnetic switch, such that if the power goes off, you have to physically go over and restart the unit, otherwise you will have single phase running through a set of windings, the motor in locked rotor state and then the magic smoke will be allowed to escape. I know this can happen as it happened to one of my clients when they left the building after a power outage and when they returned a few hours later, they were not sure when the power came back on, but it had been long enough that there was a distinct odour of burnt motor in the air. They ended up having to have the 15 HP motor rewound, then they put in the Mag switch to prevent further problems.

Walter


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