Electrical Contacts for Automotive Applications: A Review

Zhuan-Ke CHEN  Gerald J. WITTER  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.8   pp.1248-1254
Publication Date: 2004/08/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on IS-EMD2003--Recent Technical Trend of Electro-Mechanical Devices)
Category: New Technology and Automotive Applications
Keyword: 
contact welding,  contact resistance,  arc erosion,  material transfer,  automotive relays,  

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Summary: 
The three major failures of electrical contacts for automotive relay applications are: contact welding (or contact sticking), high contact resistance and severe contact erosion due to switching arcing. With the demand of high power and multiple functions of automotive vehicles, the switching current has be dramatically increased, it results in higher failing rate, in particular for contact welding. On the other hand, the miniaturization of electromechanical relays has lead to the reduction of mechanical spring force. This not only results in the earlier contact welding but also makes the relay more susceptible to the contact resistance and arc erosion failures. This paper is a review of most recent studies on these three failure aspects. It describes the progress in the understanding of contact welding caused by short arcing and high contact resistance due to contamination of particles and films in relay manufacturing process and also it review the material transfer due to switching arcing. At the end, the brief considerations of electromechanical relays used in 42 volts have also been given.