Investigation on the Switching Behavior of AgSnO 2 Materials in Commercial Contactors

The switching behavior of several varieties of Ag/SnO 2 contact materials was tested in commercial contactors and the results are compared with those obtained with standard Ag/CdO material. The properties tested were arc erosion under AC3 and AC4 conditions, contact resistance, temperature rise under continuous current, and making capacity. It was found that the newer Ag/SnO 2 -type materials, which contain WO 3 or MoO 3 in order to reduce overtemperatures, qualify as substitutes for Ag/CdO.