Step-up Transformer calculation

[pgianotto]

I have a customer with a 208V service and spec 480v equipment with a total kw demand of 133.18kw @ 480V. I need to know how to calculate what size step-up transformer I would need and also the amperage for the input @ 208V.

 

[iwire]

I have a customer with a 208V service and spec 480v equipment with a total kw demand of 133.18kw @ 480V. I need to know how to calculate what size step-up transformer I would need and also the amperage for the input @ 208V.

You would need a transformer rated at least 113.18Kw

The input current will be just a little bit more than 113.18kw

Most likely this will end up being a 150 kva transformer. (Standard size transformer is 112.5, next standard size is 150)

The input demand would be about 370 amps.

 

[Ingenieur]

what type of transformer? utility supplied pole mount? owner supplied enclosed dry type?
is the 133 kW maximum or actual continuous operating?
what is load type? motors? heating? etc

133 kW
assume a power factor of 0.8
166 kva or 460 A at 208/3
a small general purpose 150 or 225 should do it