Electrostatic oscillation in sensitive contact mechanisms

Destructive contact “frying” is particularly troublesome in sensitive contact mechanisms such as thermostats, small switches, and polarized relays. This paper describes an investigation which proved that sensitive contact frying is actually an electromechanical oscillation of the contacts and is caused principally by electrostatic attraction between the contacts. On the basis of this analysis, simple changes in contact shapes and detent arrangements are proposed as a means of efficiently eliminating the phenomenon and thus improving sensitive contact performance.