How does a reactive ballast work?

Question

I want to use a MOT (microwave oven transformer) for something it's not intended for. As a consequence, I need to limit the current so it doesn't melt itself. I am planning on connecting the ballast to the primary. The load on the secondary should be capacitive. I understand that a resistive ballast will limit current because V=I•R, so if V is constant, I will be relatively constant.

How does a reactive ballast limit current? Can I use a capacitor instead of the usual inductor? If I use both (in series) to correct the power factor, will that counteract the ballasting? Will connecting two MOTs, primaries in parallel, secondaries in series, change much?

Answer 1

A reactive ballast limits current the same way a resistive ballast does. V=I*Reactance. Yes, you can use a series capacitor to limit current. Yes, if you cancel out the capacitive reactance with an inductive reactance, the net reactance will be zero, and zero reactance won't limit the current.

If you put two transformers in parallel/series as you described, it's the same as doubling the number of secondary turns. It is doubling the number of secondary turns. And it's the same as making the primary wires twice as thick. And doubling the area of the transformer core, so it can handle twice as much primary current