A study of the pip erosion of make-only-contacts mounted on relays

摘要

Ag, Ag/SnO{sub}2 12wt, Ag/CdO{sub}2 12wt contacts mounted on a small electromagnetic relay are tested in a DC30V-10A resistive circuit as the make-only-contacts and the break-only-contacts. In this experience, we measure some electrical characteristics and observe a transferred pip on the cathode of make-only-contacts. The pip of Ag/CdO{sub}2 12wt contacts continue to grow up without collapse and the sticking occurs only at the Ag/CdO{sub}2 12wt contacts. We expect that the possibility of the sticking increase when the pip grows higher than the half of the contact gap. The Ag/SnO{sub}2 12wt contacts don't stick, because a pip collapses several times. We think the collapse of large pip prevents sticking.