Electronic control of resistance welding

After a description of the requirements of resistance welding processes the paper describes some typical electronic welding-controls. Basic circuits of timing and sequence controls are then given, together with the principles of operation of complete control units. The latest form of ¿all electronic¿ sequence timers is described. The need for synchronous control is explained, and after describing the various sub-circuits of such controls a typical complete circuit of a spot-welder synchronous control is given. The paper concludes with a brief reference to slope control of weld current.