480V Delta with 277V L-N/G

[Systems]

Hi
I was looking into the transformer in the picture attached, it says Primary 480V Delta and secondary 208Y/120V.
I get L-L 480V but I also get 277V L-N/G, does this mean that primary is 480/277Y ?? If so, How does this transformer works (Rated Delta to Wye, not Y to Y)?
Thank you

 

[infinity]

The 480 volt supply is likely fed from a 480Y/277 volt system which has a grounded neutral. When you test from phase to ground your reading the equivalent of phase-neutral on the supply side of the system feeding your transformer.

 

[chris kennedy]

Primary and secondary EGC are both bonded to the system bonding jumper allowing you to read 277V from either EGC or XO through the primary EGC back to the delta source system/main bonding jumper.

 

[Smart $]

Primary and secondary EGC are both bonded to the system bonding jumper allowing you to read 277V from either EGC or XO through the primary EGC back to the delta source system/main bonding jumper.

Wye

 

[chris kennedy]

Wye

Oops, meant "the delta sources" (wye)

Thanks:thumbsup:

 

[Smart $]

What Rob said. But to add a little more detail...

A delta primary on a transformer refers to the winding configuration, not the primary source's configuration. The transformer don't 'care' whether it is getting power from a 3? delta or wye source.

 

[Systems]

Thank you all, so i should be able to replace this with any 480V Delat Primary?

Thank you all, so i should be able to replace this with any 480V Delat Primary?

Such as the one at the link, because the transformer doesn't "care" whether the source is Delta or Star?
Thank you



http://www.elliottelectric.com/Products/Detail.aspx?v=WES&c=V48M28T30EE

 

[kwired]

Such as the one at the link, because the transformer doesn't "care" whether the source is Delta or Star?
Thank you



http://www.elliottelectric.com/Products/Detail.aspx?v=WES&c=V48M28T30EE

I think you are seeing it, the primary does not care if the source is wye or delta, or for that matter if any of the supply conductors are grounded or not. It was designed for and wants to see 480 volts nominal with 120 degree phase difference between input conductors. The neutral of a wye source means nothing to it - it does not fit anywhere into the 480 volts with 120 degree phase difference, but the other three conductors of that system do.

Kind of similar situation if you would be connecting a single phase 480 volt primary to same system. The neutral doesn't serve you any purpose as that transformer wants 480 volts input, so pick any two phase conductors and use them in that case.