AC transformers all come with two ratings for power loss (in watts): no-load loss and full-load loss.

No-load loss is a constant and will be there no matter how many volt-amps are flowing through the transformer. I understand that full-load loss goes from 0 at 0 volt-amps, to the full amount at the rated maximum of the transformer in roughly linear fashion - so if you have a 10 kVA transformer with a 100 watt full-load loss rating, then at 5 kVA you get 50 watts loss, at 10 kVA you get 100 watts loss (plus the no-load loss).

So power loss is pretty easy to calculate. But what about voltage drop? Is there an easy way to derive that from power loss? Or do I need to get inductance and resistance values for a particular transformer to calculate that?

Thanks!

Ben