Thermal Endurance of Silicone Magnet Wire Evaluated by Motor Test [includes discussion]

In October 1952 a motor test program was started at Dow Corning Corporation to evaluate a series of new modified silicone magnet-wire enamels. The purpose of this program is to determine by functional test methods the thermal life of these new enamels. Twelve 7?? horsepower induction motors insulated with silicone components and wound with wire enameled with Dow Corning 1360 wire enamel have been tested. In addition, five similar motors insulated with class-A materials have been tested to obtain data indicating the relative life-temperature characteristics of the class-A system for comparison with the silicone system. The data indicate that motors insulated with silicone components and wound with wire enameled with Dow Corning magnet-wire enamel can be operated at an average copper temperature in the range of 160 to 180 C with a life comparable to class-A insulated motors operated within their temperature limits.