Growth of Transferred Pip and Electrical Properties of AgCdO Make-Only Contacts in Resistive Circuit with DC 14 V and 42 V Power Supply

摘要

AgCdO12wt% contacts mounted on electrical relays were tested in a dc 14 V-21 A or 42 V-8.4 A resistive circuit as make-only contacts. In this experiment, we took photograph records and measured arc duration and number of bounces. A transferred pip was grown on the cathode surface, and its height H grew H/Ga > 0.5, where where H is height of pip, Ga is the contact separation, sticking occurred easily. Neither the rapidity of growth or the shape of the transferred pip influenced circuit conditions, but there were differences observed for the each sample. Since the arc discharge of switching operations at make-only contacts occurs during a rebound, the arc duration, as well as the number of bounces fluctuates.