Pre-conditioning Contact Surfaces to Reduce Dynamic Welding Tendency in Relays

Conference: Kontaktverhalten und Schalten - 18. Fachtagung Albert-Keil-Kontaktseminar
10/05/2005 - 10/07/2005 at Karlsruhe, Germany

Proceedings: Kontaktverhalten und Schalten

Pages: 7Language: englishTyp: PDF

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Schoepf, Thomas J.; Boudina, Abdellah (Delphi Research Labs, Shelby Township, MI, USA)
Rowlands, Robert (Delphi Packard Electric Systems, Warren, OH, USA)
Repp, Brent (Delphi Electronics & Safety, Troy, MI, USA)

Electromechanical switching devices such as relays may be surprisingly forgiving to occasional, but temporary, electrical stress beyond specification. Consequently delayed openings due to welded contacts on the order of milliseconds usually has been unnoticed and hence has not been reason for concern. However, as electrical systems of vehicles are getting "smarter" and more and more diagnostic routines are being implemented, even such short delay times may be translated as errors. Pre-conditioning contact surfaces has been explored as a measure to increase the welding resistance and eliminate contact opening delays. The 20 A - class relay investigated has been optimized to break occasional current peaks up to 80 ADC.