A Study on Growth of Dust of Needle-like Crystal from a Flame Retarder of Electromagnetic Relay Housing

An electromagnetic relay is an important factor in industrial process worldwide and hence there is a need for improving the reliability of relays. To enhance the reliability of an electromagnetic relay, it is mandatory to keep the contacts surface clean. However, the dust of needle-like crystal from a flame retarder of housing material may accumulate in relays an d cause electromagnetic relay failure. In this paper, firstly the sublimation/deposition of needle-like crystal is discussed, secondly temperature conditions for the formation of crystal and the direction of installing the relays are analyzed, thirdly the effects of dusts on con tact phenomena are illustrated. Finally, the investigation of how to reduce the effects of needle-like dust on contact phenomena at designing relays is discussed.