Running a transformer off of a Rotory Phase Converter

[Nutfarmer]

Are there any problems to taking the output of a 220 3 phase rotary converter and feeding it into a 220 to 440 transformer to power a 440 motor. I have a 440 motor that is not wired to change to 220.

 

[rabler]

Others may chime in with more information, but the one thing I know you need to watch out for is to have a way to disconnect the transformer to start up the rotary phase converter. Otherwise it should work reasonably well.

 

[benmychree]

Three phase transformers are not cheap, you may be ahead in the game by finding another motor, or go to an electric motor shop and have the leads brought out to connect for 220V.

 

[Nutfarmer]

It's on a Cincinnati Mono Set tool grinder. Thought about changing out the motors and using a vfd ,but the motor that turns the tool is an odd ball. Then having to rewire all the controls. All ready have the transformer. Good to know about not trying to start the phase converter with the transformer on line

 

[mksj]

Not an electrician, so worth contacting the RPC maker or transformer supplier to verify the proper type of 3 phase to 3 phase transformer. From my reading the RPC outputs 3 phase high leg delta, and the output would also be delta (no neutral reference). Sizing of the the transformer is ~1.5 kVa per Hp, and breaker on the primary side needs to be 125% of the transformer. Transformers have a momentary high in-rush current which can be an issue when powered up in paticular for large transformers. You will also want voltage taps to adjust the step-up voltage. There is an eBay listing for NOS 15 kVa transformer, otherwise if a smaller motor then a lower 6 kVa for 3 Hp or 9 kVa for 5 Hp transformer could be used.
Acme Electric T3533411S 480VAC Delta Input 15 kVA Three Phase Transformer

Acme T3533411S 480Δ Three Phase Distribution Transformer - Gray for sale online | eBay

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Discussion on the subject:

RPC output to 3 phase wye

Hi Guys, I have 208V 3 phase power at my main shop. At my home shop I have 240V single phase. Been running most stuff off of VFD and have been using diesel generators for occasionally used 3 phase equipment. But now have purchased a large format CNC router and I want to run from grid power and...

www.practicalmachinist.com

 

[markba633csi]

It'll work but it's a bit inefficient; there will be losses. It may not matter too much if it gets you running.

 

[tq60]

480 volt VFD seem to be cheaper on eBay.

Look for a single phase step up transformer and boost single phase up then use VFD.

Due to possible flash over be very carefull.

Sent from my SM-G781V using Tapatalk

 

[gunsmither]

I run a 480 volt Hardinge HLV_H on a 240 volt RPC feeding a 3phase 240 to 480 transformer. I have a time delay relay that kicks in after the RPC
is up to speed. Been running fine for years, but I hate the noisy RPC!