Electric field strength and electrical arc in the process of switching on

The paper describes the problems of estimation the electric field strength and calculating the arc switching time in contact switches during making of current in current paths and test circuits. The amount of heat power delivered to contacts as the result of electric arc ignition before metallic touching of contacts depends on parameters of the electric circuit, as well as on the size and velocity of change of the contact gap. The switching-on arc duration depends hence on the value of the intensity of electric field in the contact area, and on the velocity of contact closing.