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3ph Welder-RPC update

I posted before that Id made a quicky rotary phase converter for a 3 phase welder out of a 10hp 3450 rpm new motor and that it worked very well, but was loud as hell.

Jerry Martes gave me what appears to be a 7.5hp motor, no data plate, covered in concrete, and I fired it up yesterday. Its a 1725 rpm motor, and it did run the welder. But...it didnt run it as well as the

10hp..and it got quite hot in only a few minutes (5) weld time. Now granted it was 94F outside and the motor was in the sun, but it did get rather warmish.

I put the 10hp back on, and it ran cool and the machine liked it much better. Still sounds like a GE turbofan though..damnit.

Welder is a Airco PhaseArc 350 mig, running .035 wire at 26 volts/

100-125 amps indicated..which is considerably higher than when running on the 10hp RPC for the "same" bead penetration and look.

Ill continue searching for a 1720 rpm 10hp motor.

Btw..if anyone in So. Cal wants to make up an 5hp RPC..I have a very NICE old, incredibly heavy 1140 rpm (!) 5hp motor that should make a boffo one.

Plus I have this 7.5hp motor for a 7.5hp RPC as its not going to work for me in this application. Its hideously ugly..but it runs strong. It would make a good RPC if you were going to tuck it away out of sight

Or Ill simply gang it with my existing 5 hp commercial RPC, which isnt a bad idea at all...hummm

Gunner

Reply to
Gunner Asch
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A couple of thoughts Gunner....

Is it obvious that the noisiness of your 10hp motor is the fan? I had a

1750 rpm 7.5HP motor as an idler with no caps (I forget if you have caps on the motor). It was noisy. When I put caps on the phase converter, it quieted down quite a bit.

I've sold 5hp 1140 rpm motors to blacksmiths. If you want to end up with

200-300 rpm, you can do it >I posted before that Id made a quicky rotary phase converter for a 3
Reply to
Steve Smith

Gunner, remember the pix of the little doghouse outside for a 7.5 HP idler? There was a good reason to put it outside - noise. The caps (if you use them) can go in a box on the inside wall adjacent to the idler.

Bob Swinney

Reply to
Robert Swinney

Ayup..its the fan. No caps as yet, running stictly unbalanced

Ive got a number of gear reducers and vari-drives for that sort of work.

Gunner

Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

Reply to
Gunner Asch

Thats what Ill probably wind up doing. Im modularizing the motor, and the pony motor and will probably put it in an enclosure of some sort along with the marginally less noisy 5hp commercial RPC my shop runs off of.

Gunner

Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

Reply to
Gunner Asch

Gunner sez: "> Thats what Ill probably wind up doing. Im modularizing the motor, and

Why don't you lose that pony motor and make a starter for your idler motor? If you don't want to make one, use a Phase-a-Matic or equivalent static phase converter to start your 3-phase idler motor.

Bob Swinney

Reply to
Robert Swinney

Because I dont have a pile of caps, but I do have a pony motor. Cost is a huge factor for me at the present time.

Shrug. In a perfect world...

Gunner

Confronting Liberals with the facts of reality is very much akin to clubbing baby seals. It gets boring after a while, but because Liberals are so stupid it is easy work." Steven M. Barry

Reply to
Gunner Asch

I can give you some caps for free. Starting caps are actually not that expensive on ebay, but if you want, I can send you a few caps for nothing.

i
Reply to
Ignoramus1729

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