The Preceding Voltage Pulse and Separation Welding Mechanism of Electrical Contacts

In order to obtain a better understanding of the welding mechanism in contact separation, electrical endurance tests were conducted with AgSnO
₂
and AgNi contacts on a simulation test device. Waveforms of contact displacement, contact voltage, and current were recorded with LabVIEW during the tests, and changes in a contact gap and heights of pips with increases in operation cycles were observed through charge-coupled device cameras. The resultant test results show that welding in separation is accompanied with a preceding voltage pulse which represents arc rather than contact bounce arc.