Original poster: "S&JY" <youngsters@xxxxxxxxxxxxxxx>
Kevin,
I run two 120 volt ganged variacs. They are fed by a USA standard 240 volt
circuit (120-neutral-120 volt). One variac connects between one of the 120
volt feeds and neutral. The other one connects to the other 120 volt feed
and neutral. You can get 0 to 240 volts between the two wipers.
(David Rieben gave another response, but I don't see how his scheme could
work. Depending on which wiper to common you pick, you will end up with 0
to 120 out, or 120 to 240 out, but not 0 to 240.)
--Steve Y.