Welding tendency for selected contact materials under different switching conditions

Abstract

The flow of significant current through electric contacts may lead to contact welding. In a.c. circuits this phenomena is not only dependent on properties of contact material (i.e. resistance to welding) but on the phase in which current is switched on. Welding tendency for contact materials made from AgNi, AgCdO and AgSnO2 was evaluated based on selected phase at which make operation took place. The test circuit was protected by overcurrent apparatus to simulate real working environment. It is observed that welding tendency for the selected contact materials is contingent to current phase at which make operation is done.