Effects of Shapes of Contact Surfaces on Break Arcs Occurring between Electrical Contacts in Which a Magnet is Embedded


IEICE TRANSACTIONS on Electronics   Vol.E95-C   No.9   pp.1522-1526
Publication Date: 2012/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E95.C.1522
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electro-Mechanical Devices - Papers selected from International Session on Electro-Mechanical Devices 2011 (IS-EMD2011) and other recent research results -)
electrical contacts,  relay,  contact erosion,  permanent magnet,  high-speed camera,  

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Break arcs are rotated by the radial magnetic field formed by a magnet embedded in the pipe-shaped cathode. The arcs are generated in switching a DC42 V resistive circuit. The closed contact current varies from 5 A to 21 A. The curvature of the anode surface is varied to study the dependence of the arc length and the positions of the break arcs in the contact gap. The following results are obtained: (i) as current decreases, there is more difference in arc duration among different curvatures; (ii) as current decreases, the arc duration decreases with decrease of the radius of curvature; (iii) in each contact curvature, the anode spots region is located nearer to the center axis than the cathode spots region; (iv) the arc length just before arc extinction is independent of the curvature of the contacts.