Mechanisms of Deterioration of Electrical Insulation Surfaces

Performance tests during new product development are typically run on samples that have not been subjected to field environments. When failure of these products due to deterioration of insulation surface between metal parts of opposite polarity mounted on the insulation occurs, it is usually after many years of service and after the deposition of contaminants and moisture. This paper discusses the mechanism by which that deterioration occurs. The engineer designing insulating components should be able to use this information to avoid or at least greatly lessen the occurrence of the failure mode.