Post bridge phenomena in electrical contacts at the initial stage

Consecutive stages of contact opening are described by the mathematical model. It includes, phenomena in separating contacts before there is melting, as well as appearance, evolution, and rupture of the liquid metal bridge, the arc ignition and spreading in the bridge metallic vapors until the transformation of the metallic arc phase into a gaseous one. The calculation of life, time, and energy of each stage, contact voltage, temperature, and other extent will compare with experimental data obtained by Takagi and Hang. It is shown, that arc duration depends on opening velocity, contact scale roughness, energy, and length of liquid bridge.