230v motor on 208v?

[StaggeringGoat]

I just dragged home an old Craftsman 4hp air compressor that I got for free. The motor says 115/230v. Can I use that on my 208v 3 phase service...or am I going to have to stick to 115v?

 

[Worsedog]

It would not be a good idea. It might run but it will draw more current than it was designed to and would likely overheat.

 

[Norcal]

That is a application just perfect for a buck/boot transformer

 

[larry4406]

2nd the buck boost transformer opinion.

 

[wyliesdiesels]

First, off I highly doubt that's a 3 phase motor since it has single phase voltage listed on it. Second, like worsedog said, it will pull more current than its rated for if operated @ 208V which can cause it to over heat. U could do a buck boost transformer setup like Norcal suggested or operate it @ 120V! But it will be more efficient if you operate it @ 240V!

 

[Full Throttle]

it's not a 3 phase motor.

 

[frankzlt1]

4th the buck boost

 

[BillK]

stag,
About half of my machine shop equipment is single phase 230 or 115. It has run just fine on two legs of three phase for the 25 years I have been in business. If you have three phase power in your shop, your 115 is not really 115 anyway.
Stop worrying about it and run it

 

[Norcal]

stag,
About half of my machine shop equipment is single phase 230 or 115. It has run just fine on two legs of three phase for the 25 years I have been in business. If you have three phase power in your shop, your 115 is not really 115 anyway.
Stop worrying about it and run it

No US PoCo's supply 115 or 230V, it will be either 120/240V or 208/120V 3Ø.
A 208V rated motor should not be run on 240V, nor should a 230V rated motor be run on 208V, motors rated 115/200-230V or 115/208-230V are fine either way, older 3Ø motors rated 220/440V will be fine on either a 208 or 240volt supply when connected for lower voltage.

 

[wyliesdiesels]

stag,
About half of my machine shop equipment is single phase 230 or 115. It has run just fine on two legs of three phase for the 25 years I have been in business. If you have three phase power in your shop, your 115 is not really 115 anyway.
Stop worrying about it and run it

I'm guessing you have 240V delta 3Ø not 208Y 3Ø and that's why your equipment runs fine. What do u mean by "your 115 is not really 115 anyway"? Nominal utility voltages are as Norcal said!

 

[StaggeringGoat]

That is a application just perfect for a buck/boot transformer

If only I could drag one of those home for free.

I just remembered that I have a 10ga extension cord with twistlock ends sitting around that I can use on a 120v/30A circuit...

 

[coolreed]

If you have 208 Three Phase coming in,...

If you measure from one phase to neutral or ground you have 120 VAC.

So yes,.. you can run your 120 VAC equipment. Just utilize one phase and run your neutral and ground. Viola!

 

[wyliesdiesels]

If you have 208 Three Phase coming in,...

If you measure from one phase to neutral or ground you have 120 VAC.

So yes,.. you can run your 120 VAC equipment. Just utilize one phase and run your neutral and ground. Viola!

120V is available on a 240V 3Ø delta as well! Just make sure u don't connect anything upto the high-leg and neutral!

 

[May Pop]

There is Three phase high leg 240 volt with a neutral 120,120 190 to neutral. Then there is Delta connected 240 three phase which is completely different. NO neutral only a ground.
Delta has NO neutral.

Ron

 

[wyliesdiesels]

There is three phase high leg 240 volt with a neutral 120,120 190 to neutral. Then there is Delta connected 240 three phase which is completely different. NO neutral only a ground.
Delta has NO neutral.

Ron

No, 3 phase high leg 240V service IS delta connected! And neutral to high leg voltage is closer to 208V! You take a delta connected service and connect neutral to one of the center X2 bushings- usually on the larger of the 3 transformers!

Check out this link if you're confused:

http://en.m.wikipedia.org/wiki/High-leg_delta

 

[Norcal]

There is Three phase high leg 240 volt with a neutral 120,120 190 to neutral. Then there is Delta connected 240 three phase which is completely different. NO neutral only a ground.
Delta has NO neutral.

Ron

The high leg is 208V to Neutral.