The model of interaction between arc and AgMeO contact materials

Abstract

Based on switching experiments with cylindrical contacts of different diameters by high speed camera observations and SEM micrographs, the effects of phase change, viscosity and surface tension on erosion losses of AgMeO contact materials are analysed during arcing in the current range up to 1000 A rms. The erosion model of AgMeO is used for expressing the heat-force function during arc-electrode interaction and the liquid-solid, liquid-gas boundary corresponding to the upper and lower erosion limit respectively for the reason that erosion is composed of two modes: evaporation and minute molten droplets losses. Furthermore, supposing that the arc column is a hypothetical "point heat source" in middle of the gap, a new erosion mathematical model is established by the finite differential method and the results coincide well with those of experiments.