Erosion and resistance characteristics of AgW and AgC contacts at high current arcing in air

Even though there are numerous factors that contribute to the erosion and resistance of arcing contacts, a reliable and repeatable test has been developed for comparing the erosion and resistance characteristics of arcing contact materials over a wide current range (up to 22 kA,). Arc root current density, along with contact dimensions were parameters found to greatly affect erosion rate and contact resistance. Contact surface temperature was determined by arc root current density, which was a function of arc current. The closer the contact density was to the theoretical maximum density the lower the erosion rate of AgW. This was especially noticeable for currents above 10 kA.