Research on the Rolling and Sliding Behavior of Making Contact and Associated Welding Mechanism for Low-Current Switching Devices

The electrical lifetime of electromechanical device is affected by the contact mechanical rolling and sliding behavior greatly. The sliding distance and broadside lines of contact pair are captured
in situ
and analyzed by introducing charge-coupled device camera with a high pixel resolution. The variations in sliding distance and electrical performance parameters with operation cycles at each constant contact gap are investigated by using our novel designed test rig. The degradation mechanisms of contact surface are explained with the material transfer resulted by the continuous electric arcing. Combined with the variations in contact resistance, static force, impact force, and the scanning electron microscropy photographs of failure contacts, the degradation process and associated welding mechanisms are proposed.