Re: Variac turn-on surge solution
> I note that the breaker probably only trips when the variac is energized
> near the peaks of the AC waveform. You could install a big 25 amp solid
> state relay that is designed to switch at the zero voltage crossings. Thus
u-hum. Variac (or any transformer) is an inductive load. It has 90 degree phase
lag (ideally, in practical device some resistive component is there). If
would occur at zero-crossing point it would draw maxinum transient peak.
However, normally (pure) inductor current is zero at ac peak. So, that's when
the power should be applied. Zero-crossing switch would be much worse.
Simpliest thing is to use some resistor to feed the system and a time relay to
switch on full power somewhat later.