Contact welding regimes and characterization of silver tin-oxide electrical contact materials under short-circuit currents

Abstract The anti-welding capability of electrical contact materials directly determines the performance of low-voltage switching devices under short-circuit conditions. In this work, the contact welding behavior of silver tin-oxide contact materials under different short-circuit current peak and duration combinations. The electrical contact voltage-drop, welding force, and relative surface morphology and element distribution are analyzed. The contact welding map, which can discriminate the welding regimes with current peak and duration combinations, is presented. The map can be clearly divided into the non-welded zone, welded static zone, welded micromotion zone, and welded lift-off zone. The relationship between the welding force, the welding area and the accumulated pulse energy I 2 t are discussed explicitly. The distinct formation mechanisms of contact welding under short-circuit current are proposed.