Title :
Contact erosion in automotive DC relays
Author :
Leung, Chi H. ; Lee, Anthony
Author_Institution :
Gen. Motors Res. Lab., Warren, MI, USA
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;
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.
DOI :
10.1109/HOLM.1990.113001
