The Contribution of Heat Conduction to Bridge Length and Diameter

For electrical contacts, the liquid bridge phenomena depends on the thermal conditions. The relationship between the thermal condition and bridge phenomena is still not clear yet. Therefore, it is necessary to discuss the relationship between the thermal condition and shape of the bridge. In this paper, to clarify the relationship between the thermal condition and bridge shape (length and diameter), the contribution of heat conduction to shape of bridge is discussed. The thermal condition depends on the heat conduction from bridge to holder. To discuss the effect of thermal condition, different thermal conditions are realized by changing the heat conductivity of the electrode and the heat capacity of the holder. Firstly the contact voltage and the length and diameter of the bridge are measured, and the temperature rise of the electrode and holder are obtained by the calculation of the heat conduction. Secondly the relationship between the bridge shape and the heat conduction are discussed. In the results, the growth of the bridge depends on the heat conductivity of the electrode. As the heat conductivity of the electrode increases, the diameter and length of the bridge becomes small. As the heat capacity of the holder increases, the contribution of the heat conductivity of the electrode on the bridge becomes small. The high heat conductivity and large heat capacity can mitigate the temperature rise at the contact spot. Consequently the time variation of the diameter under the high heat conductivity and large heat capacity may be small.