Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Dwight.Crider-at-regulusgroup-dot-com>
Looks like an overload. Does the Variac get warm after a minute or two?
With any resonance or saturation effects, the load will considerably exceed
the 10 amp rating of the Variac causing it to become a limiting factor
while in the circuit. Cheers. { 8o )
Dwight Crider