Converting three phase power to single phase

I had a housemate who used a scrap 3 phase motor as the RPC to run a 3 phase lathe.

He would just connect 2 legs of the 3 phase motor across the 240V line, and use a pull string to get the 'RPC' spinning in the correct direction. Dude didn't even bother to tie the motor down; it was just sitting on the floor spinning away.

Not OSHA compliant :)
 
You know it's not all that expensive to build your own rotary converter if you pick a big 3 phase motor out of the scrap. Actually you can find most of what you need in the junk. You might have to buy the caps, but they aren't big money
 
Not nearly enough info but appears to probably be a heat pump, 5T. The 60A is likely just the circuit ampacity info and not even close to actual RLA. It is usually pretty close to assume 1HP/ton. because that appears to be a package unit, there would have to be some creative work done, but doable. Based on the first post, I don't believe the OP has the competence to engage this project. I would probably look to single phase 2 separate VFDs, one for the compressor, one for the fan motor unless the fan is converted to single phase. Many things like contactors and controls would have to be evaluated. By running a VFD on the compressor, you would avoid the inrush.

The compressor badge is the first thing to get at, and pull the real pump data to understand the needs.
 
Joethemechanic said:
You know it's not all that expensive to build your own rotary converter if you pick a big 3 phase motor out of the scrap. Actually you can find most of what you need in the junk. You might have to buy the caps, but they aren't big money
Click to expand...
I helped automate one a year or so ago. Originally they would belt up a 30 hp 3 phase to a 3/4 hp single phase pony motor. Plug in the single, get the three up to speed, apply 1Ph power to the 30, remove belt and unplug pony motor. The occasional small three phase motors would work just fine. I think 5 hp was the largest. No extra capacitors involved.
 
ptonsparky said:
The guy would have to been brainless to decide otherwise.
It will bring maybe $25 at the scrap yard if the refrigerant has leaked out for some reason. That should lessen the sting.🙂
Click to expand...
Our local Alter scrapyard will only take refrigeration units if they still contain the refrigerant.
 
You must log in or register to reply here.
Top