Utility transformer 480V Delta - Power generator 480V Wye

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rebf1203

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I have an installation where the utility company installed a 480VAC Delta transformer, and the contractor who installed the power generator has a 480VAC Wye output, both merging on the transfer switch.
As load I have a UPS system, a 150 kVA transformer (480V - 120/208V wye) and some air conditioning units.
Is this suitable?. In other word, what could go wrong?
Thanks for your help.
 
rebf1203 said:
As load I have a UPS system, a 150 kVA transformer (480V - 120/208V wye) ...
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Does the UPS feed everything on the premises, or just select loads?

I'm not sure if a 480V primary transformer cares if it's fed with 480 delta or 480 wye... I've never thought about that before :confused:

But if the other loads, like the A/C or UPS... only take delta or wye, then I think there'd be a problem when it came time to transfer over to the generator. I haven't dealt with enough 480V stuff to really know :(
 
If the utility Delta is corner-grounded, and the generator's neutral is bonded, there could be a problem.
 
The 480-208Y/120 transformer will not care. However the UPS may have problems if the neutral point, X0, of the generator is bonded to ground.
Among other issues, the bypass circuits of the UPS may not be able to be run in a closed transition mode.
 
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