What should be a resonable exciting current for a 720VA 60Hz transformer? Primary 12V/60A and secondary 110V. I'm measuring about 2A (around 3% of maximum rated current) in the primary while the transformer is idle (secondary open circuit). This is the step up transformer of my inverter project.
Another question: when the transfomer is fully loaded @ 720VA, suppose for simplification a pure resistive load, does this exciting current still represent a loss? I.e, are these 2A still wasted? I understand part of this current is just reactive and part is effectivelly loss. I'm trying to figure out the maximum theoretical efficiency of a system like this.