In this image what would be different if it were a Delta to Delta Trafo?????

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roger

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I agree with Bob.

Why do you think the transformer is a YY?

If the secondary was a Delta the voltage would not be 120/208 and the colors in the secondary panel would be wrong as far as current code.

Roger
 

kwired

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The 480/277 volts originated from a wye connected source, but it can supply a delta connected load. All the delta connected load cares about is seeing 480 volts with 120 degree phase angles.

We connect both wye and delta connected to 480 volt systems all the time. A transformer like is pictured in OP typically has a delta connected primary, if it has a wye connected primary you normally do not connect the source neutral though - you leave the "H0" terminal floating.
 
In this image what would be different if it were a Delta to Delta Trafo instead of a Y to Y trafo????

View attachment 16034

To answer your question, there are three possibilities if the secondary were a delta. 1) one winding could have a center tap which would be a grounded conductor. This would be a high leg system 2) the secondary could just be three wire with one of them grounded. This would be a corner grounded system 3) it could be a three wire ungrounded system with ground detectors. In the first two cases you would have a grounded conductor connected to a system bonding jumper and a gec.
 

roger

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I think it is an important concept for those who are learning that 1) you can connect three wires to a wye supply or source 2) "x wire" and delta wye connections refer to different things 3) one could have a wye connection but not have access to the wye point.

The way it may or may not be connected is not the give away, a Wye-Wye transformer would be shown (labeled) as 480Y/277 to 208Y/120. Since the illustration calls out a single voltage (480) it indicates a Delta primary.


Roger
 
The way it may or may not be connected is not the give away, a Wye-Wye transformer would be shown (labeled) as 480Y/277 to 208Y/120. Since the illustration calls out a single voltage (480) it indicates a Delta primary.



Roger

Sure makes sense, however that is still not industry standard transformer designation. Considering that, and that it looks like it was drawn up ms paint, I was not assuming that diagram was gospel as far as proper nomenclature. Perhaps the op will chime back in and let us know if he drew it and if he meant to say delta in the op.
 

iwire

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I think it is an important concept for those who are learning that


1) you can connect three wires to a wye supply or source

No one has said otherwise have they?

2) "x wire" and delta wye connections refer to different things

I do not know what that means.

3) one could have a wye connection but not have access to the wye point.

We could have a lot of things, but we don't have a Wye / Wye transformer in the OPs picture.
 

roger

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Perhaps the op will chime back in and let us know if he drew it and if he meant to say delta in the op.
If the Op didn't mean to say what he/she did then the whole thread was a waste of time but, I think with the effort put into the drawing it most certainly was what was meant to be asked.

Roger
 
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