Step up transformer

Doug E

New member
Originally Posted by Doug E
Have a 208 3 phase service need to add 3 phase 480v 100a panel to feed some 480v equipment ( motors )
What size transformer is needed ?
What size breaker in 208v 3p panel to feed transformer
Is disconnect needed ? Xmmf located next to panel
Where can I purchase step up transformer 120v/208v 3p primary to 480v secondary this will only be feeding 480v motors so no neutral needed
Thank-you
Doug
 
Originally Posted by Doug E
Have a 208 3 phase service need to add 3 phase 480v 100a panel to feed some 480v equipment ( motors )
What size transformer is needed ?
What size breaker in 208v 3p panel to feed transformer
Is disconnect needed ? Xmmf located next to panel
Where can I purchase step up transformer 120v/208v 3p primary to 480v secondary this will only be feeding 480v motors so no neutral needed
Thank-you
Doug
To get things started look at 450.3(B), 240.21(C), 408.36.

Probably best to use a Delta -wye and ground the 480 side, even though you don't need a neutral.

A 75 KVA would be a common some for feeding a 100 amp 480 panel, bit it could be smaller depending on what the load is. Call a supply house and get a quote.
 

jap

Senior Member
I agree.

I was going to say, probably a 75, roughly a 225 or better, the disconnect is the breaker in the panel and any local supply house.

JAP>
 
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