Evaluation of Modified Silicone Insulation Systems in Motors

Two modified-silicone conductor insulations were evaluated in motors in which the balance of the system was of conventional class B construction. These motors were tested and the results were compared with those obtained from life tests of the conventional organic-treated glass-served wire class B insulated motors. This comparison showed that class B life could be expected using either of these modified-silicone wire enamels. The results showed that use of the modified-silicone wire enamels in an otherwise conventional class H motor insulation system provided a longer life than that obtained from the same modified-silicone wire enamels when used in an otherwise class B motor insulation system. In other test motors the same two modified-silicone enamels were substituted for conventional silicone-treated glass-served conductor insulation in an otherwise class H system. The results were compared with those obtained from the conventional class H motor insulation system. This comparison showed that the life of the systems incorporating the modified-silicone conductor insulations was less than the life obtained with conventional class H motors with silicone-treated glass-served conductor insulation.