Contact erosion in automotive DC relays

Author

Leung, Chi H. ; Lee, Anthony

Author_Institution

Gen. Motors Res. Lab., Warren, MI, USA

fYear

1990

fDate

20-24 Aug 1990

Firstpage

85

Lastpage

93

Abstract

Contact degradation of automotive relays is studied in order to understand the relationships among switching operations (make, break, and make-and-break) and load (resistor, lamp, and motor). This information is essential in proper relay design, specification, and application in automotive electrical systems. Contact resistance was measured and the eroded surfaces were analysed to explain the degradation process. Significant dependence of degraded contact resistance on types of load and switching operation is found. Prominent pips and craters that can cause premature relay failures are formed during the make operation by anode-to-cathode transfer. Break arcs transferred material from cathode to anode and formed a porous layer to increase contact resistance. The amount of material transferred decreased with shorter arcing time, and also decreased with load inductance. The degradation process is explained as an interaction among switching mechanics, load current characteristics, and arc phenomena

Keywords

circuit-breaking arcs; electrical contacts; failure analysis; relays; wear; anode-to-cathode transfer; arcing time; automotive DC relays; automotive electrical systems; contact resistance; degradation process; eroded surfaces; load; load current characteristics; load inductance; relay failures; switching mechanics; switching operations; Anodes; Automotive engineering; Cathodes; Contact resistance; Degradation; Electrical resistance measurement; Lamps; Relays; Resistors; Surface resistance;

fLanguage

English

Publisher

ieee

Conference_Titel

Electrical Contacts, 1990. Proceedings of the Thirty-Sixth IEEE Holm Conference on ... and the Fifteenth International Conference on Electrical Contacts

Conference_Location

Montreal, Que.

Type

conf

DOI

10.1109/HOLM.1990.113001

Filename

113001