In a message dated 9/18/98 2:42:27 AM Pacific Daylight Time, tesla-at-pupman-dot-com writes: > I just recently got an old 40 amp variac and stripped it down to > > the core. My question is do I need to put a .125" gap in the core if Why is it always a variac. Can't you use an ordinary transformer. They are a lot more plentiful and expendable, especially 3 phase ones that I usually throw away. jim heagy