New Step down Xfrmr No load.

[Npstewart]

Im designing a project and putting a 150KVA step down Xfrmr (480Y-->208Y-3Y)for a future tenant. The tenant already knows they will need this entire load. My problem is, the only thing that will be running off of this Xfrmr is a small exhaust fan (1). (208Y-1) Until the tenant comes in with everything else and loads up the xfrmr. My question is, is it safe to have a xfrmr with a very small load on it?

 

[zog]

Im designing a project and putting a 150KVA step down Xfrmr (480Y-->208Y-3Y)for a future tenant. The tenant already knows they will need this entire load. My problem is, the only thing that will be running off of this Xfrmr is a small exhaust fan (1). (208Y-1) Until the tenant comes in with everything else and loads up the xfrmr. My question is, is it safe to have a xfrmr with a very small load on it?

Yes, in fact it is better than just sitting there not energized, when they sit the insulation absorbs moisture from the air and can fail when you energize it.

Transformers are less efficient at low loading because your core losses are constant, but that is the only issue for loght loading.

 

[Npstewart]

Just making sure, thanks for the help

 

[templdl]

Also, just prepare your customer for the electricity bill as the no load losses alone would be in the 700w area. He may think that the electric bill would be limited to the power required for the exaust fan.