Correlation of contact bounce and arc behavior for Ag-based contact materials under resistive and inductive load

To unveil the effect of intrinsic material properties, eroded morphology evolution, and electric load characteristics on the bouncing arc behavior of Ag-based contact materials, electrical contact tests were performed on Ag-8wt.%Ni, Ag-8wt.%SnO₂, and Ag-4wt.%SnO₂-4wt.%Ni contact materials under resistive and inductive loads of 18, 24, and 30 V. The arc duration, eroded morphology, and bounce characteristics were analyzed, and the correlation between contact bounce and arc behavior for the Ag-based contact materials was established. It is found that different arc states are present during each bouncing process and thus exert a profound impact on the make-arc duration. A larger bounce height is observed for the Ag-8wt.%Ni contact material because of its high elastic limit. However, for the Ag-8wt.%SnO₂ contact material, greater bouncing energy loss arises from the stress concentration on SnO₂ particles. Moreover, good bonding between the Ag matrix and the eroded layer is beneficial to bounce, whereas separation of the eroded layer gives rise to bouncing energy loss, thereby decreasing the bounce. Additionally, because temperature rise and stress release occur at the contact spots due to the rapid response to current, a small bounce height is observed under the resistive load and at higher voltage. In contrast, a large bounce height occurs under the inductive load without the presence of a sharply increased current.