Direct current arc quenching performance of a model electric fuse equipped with SiO2 sand and additive silicone resin as an arc quenching medium: the effect of a vaporized silicone decomposition mixture on transient arc resistance

Abstract Most high-power electric fuses installed in DC distributions of automobiles employ silica sand (chemical formula SiO 2 ) as arc quenching material to implement the limitation and subsequent interruption of high direct currents. This paper on arc quenching material describes the effects of the addition of silicone resin (chemical formula C 2 H 6 SiO) on SiO 2 sand, based on the resistance of an arc discharge in SiO 2 vapor mixed with silicone resin vapor. The measurement results obtained for the fuse operation of a model electric fuse show that the addition of silicone resin, e.g. an even coating of silicone resin on the surface of a Cu fuse element, attains a shorter arc quenching time. This phenomenon is subsequently explained based on the rise effect of an arc column resistance achieved by mixing with silicone vapor decomposition. The chemical compositions of high-temperature SiO 2 vapor mixed with C 2 H 6 SiO vapor decomposition are evaluated to show the predominant chemical species at 30 000 K–5000 K for several C 2 H 6 SiO vapor concentrations, X C H . The results obtained for X C H of 10%–50% reveal that a H atom originating from C 2 H 6 SiO is present at high molar fractions above 0.1 over a wide temperature range of 12 000 K–5000 K. Further evaluations of the electrical resistivity ρ R for the high-temperature vapor show that mixing with C 2 H 6 SiO vapor contributes to a rise in ρ R at temperatures of 10 000 K–6000 K. A contribution analysis of the ρ R reveals that the rise effect of the ρ R is accomplished chiefly by the presence of a H atom that has dissociated from C 2 H 6 SiO.