Abstract: A high voltage circuit interrupter has a surface modified pulverulent arc-quenching filler composition, with gas-evolving material is bound to the surfaces of the arc-quenching filler by a binder. The pulverulent arc-quenching filler can be selected from the group of silicas and silicates, preferably sand, mica or quartz. The gas-evolving materials can be selected from the group of melamine, cyanuric acid, melamine cyanurate, guanidine, guanidine carbonate, guanidine acetate, 1,3-diphenylguanidine, guanine, urea, urea phosphate, hydantoin, allantoin, and mixtures and derivatives thereof. The device has a generally tubular casing of electrically insulating material, terminal elements closing the opposite ends of the casing, at least one fuse element conductively interconnecting the terminal elements, a core for supporting the fuse element, extending parallel to the longitudinal axis, and a modified pulverulent arc-quenching filler material inside the casing, in close proximity to the fuse element.

Abstract: Arc-quenching coating compositions are provided with effective arc-extinguishing properties and improved track resistance properties, and are relatively easy to apply in liquid form. The coating compositions are used, for example, in high voltage current limiting fuses, expulsion fuses, circuit breakers, circuit interrupters, separable cable connectors, or the like for interrupting circuits. The arc-quenching coating compositions include an arc-quenching gas-evolving material (A) and a film-forming polymer (B) having minimal tracking properties, in which the film-forming polymer (B) acts as a liquid vehicle for the coating composition. The arc-quenching material (A) is preferably selected from the group of guanidine, guanidine carbonate, guanidine acetate, 1,3-diphenylguanidine, guanine, melamine, melamine cyanurate, urea, hydantoin, allantoin and derivatives and mixtures thereof.

Abstract: A striker pin device for providing a visual indication of an operated condition of an associated fuse, comprising a tubular housing coaxially arranged within the fuse with an end of the housing in contact with an end of the fuse. The tubular housing has a closure structure comprised of a one-piece integrally formed closure member having a projection protruding out of the housing and an opened end with a cavity. A piston with a central projection received in the opened end of the closure member forms a gas tight enclosure containing pyrotechnic material. An ignition element is attached to a brass pin which extends through the projection of the closure member and is connected to a tubular terminal or electrical conductor member which is attached to a high resistance pilot wire, which is stretched through the fuse.

Abstract: Effective arc-quenching is desired for current interrupters as defined to include circuit breakers, contactors, fuses and the like under conditions of operation where an electrical arc is produced that must be quenched to eliminate an undesirable current flow. An improved mode of arc-quenching coatings comprising urethane, melamine and acrylic based resin compositions containing inorganic nitrides such as boron nitride, aluminum nitride and silicon nitride are found to be effective as arc-quenching materials for current interrupters. Other coating compositions comprising urethane, melamine and inorganic nitrides mentioned above and high nitrogen organic compounds such as urea, hydantoin, allantoin, guanidine carbonate, guanine, melamine cyanurate and 1,3-diphenyl guanidine are also found to be effective as arc-quenching materials for current interrupters.