Study of the Effect of Contact Material Arcing Deposits on the Surface Resistance of Insulating Materials

A method is described for applying a power arc, which is burning between various contact materials, against insulated surfaces in a controlled way in order to measure the effect on insulation surface resistance. The purpose of the test is to provide a method to evaluate insulation material for use in switch interruption chambers. The results of tests using fine silver, coin silver, silver nickel, and silver cadmium oxide contact material and three types of insulating materials are reported. Variations found in contact resistance patterns and size of erosion and contamination area are presented and discussed.