277 to 120 step down transformer question

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mkgrady

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Massachusetts
I need to feed a 120 volt control panel and the only power nearby is a 277/480 volt panel. I need about 1.5 to 2 KVA. I'm waiting to hear the actual load so my question is theoretical. I hope to find a transformer with a 277 primary and a 120 secondary. If I can find that in the KVA I'm looking for then I am all set.

I have found a couple of versions of transformer that have the right primary voltage (because they list multiple voltages) but the secondary is 120/240. If I am only using one leg of the output will I get the full VA rating on just one of the legs to neutral?
 
mkgrady said:
I have found a couple of versions of transformer that have the right primary voltage (because they list multiple voltages) but the secondary is 120/240. If I am only using one leg of the output will I get the full VA rating on just one of the legs to neutral?
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The secondary can't be wired in parallel to provide only 120?
 
Most transformers will have two secondary windings that can be connected either series or parallel. Connect parallel for 120. Consider using a 480 volt primary, it will put the load on two phases instead of just one.

View attachment files.pdf
 
dkidd said:
Most transformers will have two secondary windings that can be connected either series or parallel. Connect parallel for 120. Consider using a 480 volt primary, it will put the load on two phases instead of just one.

View attachment 15647
Click to expand...

I think there is a spare single phase breaker in the panel. I put a couple of three phase breakers in this panel and I choked on the cost I would think this load would be small enough where balancing the panel would not matter. I installed a couple of 40 amp three phase breakers in this panel and choked on the cost ($500 each)
 
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