120/208y - 480 delta

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spider2

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is there any way to get a neutral when going from 120/208Y to 480 delta. The wrong transformer was ordered and someone asked if we could just use the same neutral from the primary side for the secondary. I didn't think so but figured I would check here.
 
Re: 120/208y - 480 delta

I agree with Wayne in that "No".

A neutral is created by the "Y" configuration of a three phase transformer.

I would attempt to get the transformer exchanged for the correct one. The suppliers I deal with will work with me on just about anything.

And Don't you have to ground the secondary?
 
Re: 120/208y - 480 delta

The neutral of a transformer for which the line-to-line voltage is 480 volts will give you a single phase voltage (line-to-neutral) of 277 volts. That 277 is what is needed in your situation, and it cannot be derived from a delta configuration. Tell them to send it back and give you the right transformer.
 
Re: 120/208y - 480 delta

Coincidentally, on Friday I got a call from a former student asking about the opposite situation. They were needing a normal step-down 480 delta to 120/208 wye xfmr. But the supply house had sent out a 208 to 480 step-up xfmr. He asked if they could just hook it up with the 480 as primary and get the 120/208 from the other side. My first reaction was "yes" but I got him to draw the nameplate and fax it to me.

The primary was a 208 volt delta and the secondary was 480/277 wye. So, he could not use the xfmr "backwards" to derive 120/208.

A 208 delta to 480/277 wye is exactly what is needed in the case in question of this thread.
 
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