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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 5399
Experience:  Proven Professional 45 years Experience
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i have a transformer question I have never done before.Pics

Resolved Question:

i have a transformer question I have never done before.Pics of all are availb.
Feed a 300 kva trans with 208 3phase 800 amps. secondary 400 volt 400 amp
with a 120 volt high leg.
The trans they sent is Primary 480v delta with fc taps. Secondary 240-120 high
leg delta. There is no xo tap on either side, only a frame grnd. They want to
feed the 208 side and get 400 volts 3 phase and 120 single phase out. in other
words backwards. Where does the neutral come from other than the frame on
the high side? i can send pich of all if i have your e-mail
Submitted: 1 year ago.
Category: Electrical
Expert:  Mike G. replied 1 year ago.
Hi, I'm Mike and I'll be glad to assist you. Are you trying to get 277/480V? If so from your description it isn't possible on that transformer. Only 480V secondary is possible
Customer: replied 1 year ago.

The trans is taped to get to get 423 volts. I can't see where the neutral


for the 120 volt is coming from other than eq grnd on the 208 side.


taht can' t work can it . I have pics of all the diag. if u need

Expert:  Mike G. replied 1 year ago.
You can get 423V and the primary is 3 wire 208V, there isn't a neutral required.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 5399
Experience: Proven Professional 45 years Experience
Mike G. and 3 other Electrical Specialists are ready to help you
Customer: replied 1 year ago.

Thats the problem they want a 5 wire system on the 423 side and I


don" see how to get it other than eq ground on the 208 side. I think


 


it"s a bad idea and the wrong transformer

Expert:  Mike G. replied 1 year ago.
iIf your required secondary is 423V 3 phase, you can use a 208V primary. North will only be 3wire and a hround... If you need 277/480V then the additional conductor is requited and you have a Delta-Wye Transformer and it is wrong. A Wye wye transformer is needed
Customer: replied 1 year ago.

Thanks that is what think. trans wont work,

Expert:  Mike G. replied 1 year ago.
You're welcome

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