Electric and Spectroscopic Characterization of Arcing in Electrical Contacts: A Study of Erosion

Arcing in electrical contacts of telephone switching relays and the subsequent erosion have been the subject of a great deal of work. Nevertheless the problem depends on many parameters (the electrical circuit, environment, relay type, etc.) and knowledge is incomplete. The AgCu 90/10 contact used in the French CP 400 telephone switching system and, more particularly, the consequence of arcing in the current range 1-500 mA are the subject of this paper. Two methods are used to study arcing: measurement of the arc duration and analysis of the emission spectrum from the arc. The first results show that these two arc characterizations are related to erosion and that the variations with current are similar.