Effect of the Thermal Constant on Temperature Rise of Silver Palladium Alloy Contacts

Kazuaki MIYANAGA
Yoshiki KAYANO
Hiroshi INOUE

Publication
IEICE TRANSACTIONS on Electronics   Vol.E90-C    No.7    pp.1405-1411
Publication Date: 2007/07/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.7.1405
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electromechanical Devices (Selected Papers from ICEC2006))
Category: Contact Phenomena
Keyword: 
electrical contact,  silver palladium,  temperature rise,  FDTD,  thermal constant,  

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Summary: 
In this paper, a method of separating the effects of the thermal diffusivity, durations and integral powers of the bridge and arc on the temperature rise of AgPd contacts was proposed. First, the effects of the Pd content on the durations and integral powers of the bridge and arc, and the temperature rise of the contacts were discussed. Because the integral power of bridge was larger than that of the arc under our experimental conditions of 40 V open-circuit, 5 A close-circuit and 100 µm/s opening velocity, the temperature rise of the contacts was dominated by the bridge. No remarked difference in bridge duration can be seen among the six materials. Although the integral power of the bridge in the case of Pd was maximum, the maximum temperature rise of the contact was observed in the case of AgPd60. To clarify the contribution of each factor, the effect of thermal diffusivity on the temperature rise of the contact was evaluated by the finite-difference time-domain (FDTD) method. In the case of Pd, because its thermal diffusivity was largest, heat diffused rapidly. On the other hand, the thermal diffusivity in the case of AgPd60 was small, and heat diffused slowly to the holders. The maximum temperature rise was observed in the case of AgPd60. It was demonstrated that the proposed method of separating the effects of thermal diffusivity, durations and integral powers of the bridge and arc on the temperature rise of contacts is effective in enabling us to understand contact phenomena.