A transformer includes a stator core, primary coils, secondary coils, and heat radiating plates each of which projects outward from between interior layers of the primary coil and/or secondary coil. An A.C. arc welder includes the transformer therein, with a movable core which can move to and fro between...http://www.google.com/patents/US5660749?utm_source=gb-gplus-sharePatent US5660749 - Transformer and A.C. arc welder
