transformer

[mkt1979]

I am opening a new fabrication and manchine shop and will have 480/277 service. What will I need for a transformer to get my 220 and 120 single phase?

 

[rbulsara]

A 3-phase step-down transformer with 480V delta primary and 208Y/120V secondary.

220V loads would run fine on 208V. You get 120V between any phase and the neutral. If there a very sensitive 220V equipment, you can use a buck-boost transformer for that particular unit.

Where possible, try to get 208V rated machines.

 

[weh3]

Most plants can be operated without 220 (or 240, whatever you want to call it). You will probably end up with a 45kVA 480 to 208Y/120V three-phase dry-type transformer mounted on a concrete pad on the floor. At 208V, a 30 kVA xf will serve a 100A main breaker, 45kVA will serve a 150A MB.

William

 

[jghrist]

Discuss your needs with a utility representative. They may be able to supply a separate 120/240 volt service economically.