Abstract
In make and break of relay, arc is generated in the cut off in general. The temperature reaches several thousand degrees at the contact point. Heat generated by the arc causes the consumption of contact and leads to the premature failure. It is known that consumption of contact is strongly related to the contact volume from previous experiences. On the other hand, cost of contact material is a large proportion among the relay. So it is inversely proportional to the contact cost and life. In this paper, a simplified one-dimensional unsteady-state thermal analysis has been examined, and the contact volume which satisfies both cost and a life is able to be optimized by using this technique.
