Dependence of Motion of Breaking Arc on Contact Separating Speed for Ag and Pd Contact Pairs in a DC42V Resistive Circuit

Yoshinobu NAKAMURA  Junya SEKIKAWA  Takayoshi KUBONO  

IEICE TRANSACTIONS on Electronics   Vol.E90-C   No.7   pp.1361-1368
Publication Date: 2007/07/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.7.1361
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electromechanical Devices (Selected Papers from ICEC2006))
Category: Arc Discharge & Related Phenomena
electrical contact,  arc spot,  breaking arc,  separating speed,  high-speed video camera,  

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Ag and Pd electrical contact pairs are separated at constant separating speeds (5, 10 and 20 mm/s) in a DC 42 V/8.4 A resistive circuit. The motion of the breaking arc is observed with a high-speed video camera. For Ag contacts, the motion of the breaking arc becomes stable at a certain critical gap at separating speeds of 10 mm/s and 20 mm/s, and the breaking arc moves extensively at the separating speed of 5 mm/s. For Pd contacts, the breaking arc moves extensively regardless of the separating speed. These results are attributed to the following causes. For Ag contacts, the difference in the motion of arc spots at each separating speed is changed by the difference in the total energy input to the contacts. For Pd contacts, the temperature of the contact surfaces is kept high because of the lower thermal conductivity of Pd than Ag.