THE MODEL OF INTERACTION BETWEEN ARC AND AGMEO CONTACT MATERIALS

Based on switching experiments with cylindrical contacts of different diameters by high-speed camera observations and SEM micrographs, the e ffects of phase change, viscosity, and surface tension on erosion loss es of AgMeO contact materials are analysed during arcing in the curren t range up to 1000 A rms. The erosion model of AgMeO is used for expre ssing the heat-force function during arc-electrode interaction and the liquid-solid, liquid-gas boundary corresponding to upper and lower er osion limits, respectively, for the reason that erosion is composed of two modes: evaporation and minute molten droplets losses. Furthermore , supposing the arc column is a hypothetical point heat source in midd le of the gap, a new erosion mathematical model is established by fini te differential method, and the results coincide well with those of ex periments.