Abstract: A method for operating a circuit-breaker by means of which one is able by using a vacuum circuit-breaker, to interrupt inductive circuits without causing disturbing overvoltages. The switching operation of the vacuum circuit-breaker is influenced by a tripping control device, which is supplied with a measured value of the tripping delay of the vacuum circuit-breaker from the instant the tripping signal is output to the instant the contact members are separated as a correcting quantity, in the case of an opening operation that occurred previously. The temperature of the actuator unit of the vacuum circuit-breaker, the standstill time of the circuit-breaker, as well as the operating voltage and temperature of a tripping solenoid can be used as further correcting quantities. The described method is suited for application vacuum circuit-breakers in circuits with inductive components.

Abstract: The invention is directed to a quenching and contact arrangement for a compressed-gas circuit breaker. The arrangement includes a tubular contact piece and a contact piece axially arranged therewith. An arc is drawn between both contact pieces when the circuit is interrupted under load, the arc then being blasted by a stream of compressed-gas. A turbulence grid is arranged in the flow path of the stream. The turbulence grid is configured in the form of a tube of insulating material with perforations in the cylinder surface thereof which directly encloses the arcing space in the course of the circuit-breaking motion.

Abstract: A contact system for power circuit breakers includes a nozzle body made of graphite which is pressed cold into a tube of cold-worked copper and is enclosed by the latter with a friction fit. A low-alloy copper is used as the material for the electrically conducting tube. Such a copper alloy can be made, for example, with 0.1 percent silver.