Experimental research and computer simulation process of pulse heating high current contacts of vacuum interrupters

One of the major factors limiting magnitude of currents passing through the contacts of vacuum inter-rupters is the possibility of electrode melting and following welding of electrodes with pulse currents of high amplitude. Research of processes of melting is complicated because of their significant non-linearity and non-stationarity. In full formulation it is necessary to solve a joint thermoelectromechanical problem. Today there are no effective numerical techniques that allow one to obtain a solution in a wide range of temperatures up to the melting point of electrode material. This study contains experimental research of processes of heating and welding of contacts of standard configurations by pulse currents of industrial frequency. Time dependences of contact resistance and voltage on contact junction have been recorded and analyzed at various amplitudes of proceeding currents. As a result of the numerical modeling based on received experimental data, temporal dependence of temperature in the field of contact has been determined; dynamics of change of the size of contact stains has been discovered; conclusions have been drawn about possible mechanisms of occurrence of welding; dependences of tearing force of welding on size of proceeding currents have been derived.