Metal-Filled Polymer Combining Electric Conductivity and Gas Blasting

Metal-filled polymer (MFP) electrodes are presented producing extensive interactions with the switching arc. These electrode materials have an electric conductivity of a few percent of a good electric conductor like copper. Under the thermal stress of an arc spot they evaporate hydrogen and other gases yielding a strong axial gas blast effect on the arc column. Thus arc voltage and arc extinguishing capacity during current zero interval are remarkably increased. Also additional fillers like polytetrafRuor0ethylene (PTFE) may favor the arc extinguishing properties. The current carrying capacity and the Switching performance of a typical metal-filled polymer is discussed using a simple electrode arrangement especially suited for this material.