Transient Phenomena from Melting to Electric Discharge during Making and Breaking Operations of Electric Contacts

During breaking contact, contact voltage vc shows irregular, random, or unexpected responses after vc=Um until mechanical contact current shutdown or arc ignition. The dependencies of the phenomena on energizing current and residual inductance were confirmed. Different contact materials (Ag, Au, Ir, Pd, Pt, Zn) show the same contact current and voltage features. Measured index values are slightly different. Combined contact of Pt and Zn electrodes shows that the phenomena mainly depend on the negative electrode metal. In our paper, it is confirmed that the so-called "initial arc" phenomenon has a close relation with arc ignition, but is independent of arc phenomena.