Vacuum Contactors for Rubber and Plastic Mill Drives

A brief historical background to vacuum contactors development is given. Comparisons are made between air and vacuum arc extinction, and a successful vacuum contactor design is described. Details of field experience are given. Particular reference is made to improvement in dynamic braking performance made on a 2300-volt rubber mill drive. Suggestions are made for further improvement, and a low-tension plug braking vacuum contactor starter is discussed.