Size And Type Of 3 Phase Transformer?

Be a lot cheaper to have the motor re-wired to run on 220V's as John said to do.

I've done this same thing on two-speed motors over the years. One case, even re-wired it back to 440V!
 
4gsr said:
Be a lot cheaper to have the motor re-wired to run on 220V's as John said to do.

I've done this same thing on two-speed motors over the years. One case, even re-wired it back to 440V!
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I think there may be some confusion here. Rewinding, which is what I suggested, involves taking the motor completely apart, unwinding the armature, and rewinding it for the new voltage. Not cheap, but probably cheaper than a new motor. It's what motor rewinding shops do (among other things). Rewiring would usually involve changing the existing windings from series to parallel. That option is evidently not available here.
 
Hi Ropata, I hope I have not steered you in the wrong direction?

markba633csi said:
I think you might have rushed into this- Myself I probably would have done the step-up first in single phase then used a vfd to get the 440 three phase... If I was determined to use the original motor. You still could do that and maybe use the rpc for other stuff. The direction you are going now won't be the most efficient and the 3 phase transformer will be pretty buzzy. Not to mention expensive and BIG.
Mark S
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My experience with the RPC + transformer performs well. I can't comment on how efficient it is - nothing gets very hot, the power bill hasn't changed much, the machines work well. Of course, the more devices in the system, the lower the efficiency & reliability are going to be. Mark is right about the buzzing noise, though it is still quieter than my RPC - I do have them located in a seperated part of the garage (along with the air compressor) - with the dividing door closed all is good.

Big? Perhaps that depends on how much room a person has. My 6kva transformer has a bit smaller foot print than my 5HP RPC. The spec sheet should identify what the dimensions are and you could decide if that would be workable in your situation.

For multiple machines and easy controls, it is hard to beat the RPC option.

Reading about your efforts to find a transformer, I consider myself very fortunate to have found a, tested working, 240-575V, 3 ph, 6kva in close driving distance for $100. I certainly thought it was a good deal at the time and acted on it immediately (I didn't haggle on price and got there before he changed his mind).

Good luck, David
 
Chipper5783 said:
Hi Ropata, I hope I have not steered you in the wrong direction?



My experience with the RPC + transformer performs well. I can't comment on how efficient it is - nothing gets very hot, the power bill hasn't changed much, the machines work well. Of course, the more devices in the system, the lower the efficiency & reliability are going to be. Mark is right about the buzzing noise, though it is still quieter than my RPC - I do have them located in a seperated part of the garage (along with the air compressor) - with the dividing door closed all is good.

Big? Perhaps that depends on how much room a person has. My 6kva transformer has a bit smaller foot print than my 5HP RPC. The spec sheet should identify what the dimensions are and you could decide if that would be workable in your situation.

For multiple machines and easy controls, it is hard to beat the RPC option.

Reading about your efforts to find a transformer, I consider myself very fortunate to have found a, tested working, 240-575V, 3 ph, 6kva in close driving distance for $100. I certainly thought it was a good deal at the time and acted on it immediately (I didn't haggle on price and got there before he changed his mind).

Good luck, David
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Three phase transformers are smaller and lighter for the same KVA than single phase ones.
 
I still think you should take the motor to a motor shop and get a price on rewinding it for 240.
 
I was told It wasn't possible to re-wind. 20160606_201434.jpg Can you see any reason why not? Is re-winding quite cheap?
 
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