Experiments on dependency of metal mixing ratio in Ag‐Pd alloy contacts on breaking arc duration, metal erosion and transfer

Breaking arc durations and the differences between the mass of a contact before and after an experiment which is a quantity of metal erosion and transfer (QMET) were measured in Ag‐Pd alloy contacts. The experiments were performed in air under particular combinations of voltage, current, and opening speed. The effects produced on arc duration and QMET by different proportions of metals were investigated. In a practical Ag 40 wt% contact, the arc duration was not especially longer and the metal loss was not more than the other ratios. In an Ag 90 wt% contact, the arc duration had a large tendency to become longer under certain conditions and the metal loss was large. The arc duration of Ag 20 wt% had a tendency to become long with the number of operations. The characteristics of arc durations and QMET were different due to two ways of fixing a columnar contact from one side to a holder and from two sides. The curves of QMET were zero‐crossed and the mixing ratio for QMET became zero for one of the two electrodes. This paper possibly suggests some way to design electrodes for heat produced in the Ag‐Pd alloy contact, and the possibility of zero QMET.