A study of contamination levels measurement techniques, testing methods, and switching results for silicon compounds on silver arcing contacts

Silicon compounds, both inorganic and organic, are detrimental contaminants for arcing electrical contacts. The authors review past work and introduce new data correlating contamination levels with switching performance. Methods for measuring silicon contamination on the contact surface by use of an energy dispersive X-ray analyzer (EDXA) are described. The difference in mechanisms with both mineral and silicone types of contamination is explained. Silicone contamination build up is controlled by migration rate and breakdown of silicones in the arc. Mineral (grit) contamination reacts immediately with the arc and affects early switching life of contacts.<>