The use of D-C overpotential testing as a maintenance tool in the industrial plant

Electric apparatus represents a large portion of the equipment required for productive activities in the industrial plant: generators to produce power; cables, transformers, and switch-gear for transmission and distribution; and motors for transforming electric energy into mechanical power. Insulation, the critical part of electric apparatus, has a limited service life, a variable depending upon the deteriorating and contaminating factors associated with the operation of the equipment. Production interruptions and unnecessary damage from insulation failures represent an economic waste in industry. Needless replacement of insulation, primarily on the basis of age and visual inspection, without substantiating data of its being in questionable condition, further adds to economic waste. As an obvious deduction, there is a definite need for a test which will reliably evaluate the condition of insulation for continued service.