# Delta/wye



## hydro (Aug 21, 2009)

I have a customer that bought a 38 kw generator for backup power at his shop. Generator puts out 208 3 phase, shop is a 600 volt 3 phase wye service with nothing connected to the neutral. Can I reverse wire a 45 kva transformer to feed the shop with no neutral? I don't have a lot of experience with delta systems and corner grounding and what not. Thanks in advance.


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## Meadow (Jan 14, 2011)

600 volt delta is not the same as 600 volt wye without the neutral used. 

A 208 volt delta, 600 volt wye transformer is your best bet outside of a new generator. However, look to see if the generator is reconfigurable in any way. A lot of US generators can be configured from 120/208 to 277/480 via windings and voltage adjustment.


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## hydro (Aug 21, 2009)

Yes I haven't seem the generator first hand yet but I have yet to see one that couldn't be switched to 277/480 however that still doesn't do me very much good. I wish they were more common in 600 volt setting


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## micromind (Aug 11, 2007)

Whether or not a backfed transformer will work depends a lot on the loads it feeds. 

If the 600V service feeds stuff that doesn't care if one leg is grounded or not (like across-the-lines motor starters and transformers, but not VFDs, then a backfed transformer with a 600V ∆ would be ok, just ground one of the phases. 

If there are VFDs or anything else electronic on the 600V system, then a backfed transformer with a 600V ∆ won't work. 

A transformer with a 600V Y will be the same as the service.


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## hydro (Aug 21, 2009)

Perfect thanks for the response. It's all motor loads and transformers stepping down to 120/208. The only load otherwise is an old 600volt welder that doesn't appear to have any electronic a in it and doesn't seem to be used that often anyways. Plus it doesn't require a neutral.


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