Step Up Transfromer 208V-to 277V

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faresos

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Helloe every one,

I have a situation where an engineer have specified a step up transformer (9KVA)from 208V (single phase) to 480V/277V (single phase). I have looked at multiple manufacturers catalog and could not find any transformer with this specification. Does anyone know someone makes it? also, the contractor have submitted a step up transformer instead with 208V-to 277V, and the down stream panelboard is single phase. How can we wire the secondary of the transformer (277V) to a single phase panel with two busbars?

Any help will be appreciated.
 
I'm just reviewing a submittal and they have already ordered it (208 to 277V). Now I have to deal with it unless someone makes it without a custom made. Now i just need to know how could be wired to a single phase panelboard. Thanks,
 
faresos said:
I have a situation where an engineer have specified a step up transformer (9KVA)from 208V (single phase) to 480V/277V (single phase).
Click to expand...
There's no such thing as a single-phase transformer with a 480/277v secondary; it's one or the other.

... the contractor have submitted a step up transformer instead with 208V-to 277V, and the down stream panelboard is single phase. How can we wire the secondary of the transformer (277V) to a single phase panel with two busbars?
Click to expand...
Presuming you bond one conductor, you'd split the ungrounded conductor to land on both line terminals.
 
First of all 480/277 IS 3 phase not single phase.
208 volts is derived from a 120/208 volt 3 phase system.
Using (3) single phase 208 volt transformers connected in a DELTA configuration will transform to 277/480 volts WYE. 3 phase transformers are also available.
A 3 phase panel will be required for distribution.
The "engineer" is not providing a clear design. As usual.

BILLY
 
oh yeah....a single phase transformer is going to be 120/240 <-> 240/480 you could get a custom 208 to 480 but thats about it.
 
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