New contact material for reduction of arc duration for dc application

¹ Metalor Technologies (France) SAS, Electrotechnics Division, BP 29, 28190 Courville-sur-Eure, France
² University of Rennes 1, IPR, 35042 Rennes, France
³ CRETA, CNRS, 25 avenue des Martyrs, 38042 Grenoble, France
⁴ Institut Néel/CNRS-UJF, 25 avenue des Martyrs, 38042 Grenoble, France
⁵ Metalor Technologies SA, Technology Products Department, 2009 Neuchâtel, Switzerland

Corresponding author: Laurent.doublet@metalor.com

Received: 28 November 2008
Accepted: 21 January 2010
Published online: 26 February 2010

Abstract

The phenomenon of arcing is the major cause of electrical contact degradation in electrical switches. Degradation involves contact erosion and/or welding. The use of special contact material and that of specific material processing may permit contact erosion to be reduced, in particular by shortening the arc duration. A short review of these approaches is presented in the first part of this paper. In the second part, the development of a new self-blowing contact material is described. This material has been tested under dc voltages from 14 V to 42 V. A reduction of the arc duration by a factor of 4 approximately was obtained as was a concomitant reduction of the extinction gap to less than 2 mm. This material will contribute to achieving better reliability in high current-high voltages breaking devices, and will aid in their miniaturization, e.g. in relays.