Variation of Arc Duration of Electric Contacts Due to Controllable Atmospheric Condition

A new measuring system Of contact phenomena has been developed, which can control noncorrosive atmospheric conditions such as air pressure, mixture of air and noncorrosive gas, and electrode temperature. The developed system is controlled by a microcomputer and measured quantities can be processed also by the microcomputer, and the final data can be printed Out and/or displayed. Arc duration and contact resistance can be measured under several atmospheric conditions at fixed contact opening speed. Contact materials of Ag and Pd were tested, and many interesting results for variation of arc duration have been obtained. For example, the variation of the arc duration for Ag and Pd contacts has a different tendency from each other with respect to the atmospheric pressure, and the variation of the arc duration relates the contact resistance.