Ratings and Applications of Power Thyristors for Resistance Welding

Guidelines are given for applying SCR´s in resistance welding controls. The stresses the SCR´s are subjected to in resistance welding applications due to the cyclic nature of the load are discussed from a device, design, and application point of view. In addition the special rating of SCR´s and cooling requirements for cyclic duty are described along with techniques for protecting the devices from overvoltage, overcurrent, and loss of coolant. Gating requirements are outlined from a circuit view point.