Abstract: The circuit breaker displays a commutation device (4) and a semiconductor valve arrangement (6) which is connected in parallel with the commutation device (4), an isolating switching point (5) connected in series with the semiconductor valve arrangement (6) and a control circuit (11). The control circuit detects the polarity of the current to be disconnected and, together with a switching-off command (24), emits a response command to the commutation device (4) when the detected current flows in the direction of conduction of the semiconductor valve arrangement (6). When the current to be disconnected is interrupted in the semiconductor valve arrangement (6) after the commutation device (4) has responded, the control circuit (11) emits a release command to the isolating switching point (5) forming an isolating gap. As a result, the semiconductor valve arrangement (6) is isolated and the switching-off process is terminated.

Abstract: The switching system, preferably suitable for distributing electric energies of medium-high voltage, includes a metal housing which is filled with insulating gas and in which at least one circuit breaker, one isolating switch, one earthing or grounding system and one busbar are arranged. In this arrangement, the contact arrangement of the circuit breaker is located in a housing which is accessible from the outside without intervention in a busbar housing which contains the busbar. This system saves parts and has a small space requirement while its components subject to the most wear are easy to maintain. This is achieved by the fact that the contact arrangement of the isolating switch is provided in the busbar housing and that the housing of the circuit breaker is provided with a housing part of insulating material which penetrates the wall of the busbar housing as a gas-tight current lead-through.

Abstract: The gas-blast switch preferably suitable for the switching of medium voltage contains two switch pieces (2, 3), which are movable relative to one another in a housing (1), filled with insulating gas, and define an arc-quenching zone (4) during switch-off. Moreover, the arc-quenching zone (4) is defined by an insulating body (8) in which an annular channel (15) is recessed. The annular channel (15) connects the arc-quenching zone (4) with a chamber for the storage of heated-up insulating gas. Additionally compressed insulating gas can be fed to this storage chamber (9) from a compression chamber (10) of a compression device which is actuated during switch-off. In this switch, the switch-off capacity is to be increased by improving the quality of the insulating gas located in the storage chamber (9). This is achieved in that the compression chamber (10) and the storage chamber (9) are connected to one another via a flow narrow point (18).

Abstract: In this isolating switch, which is suitable for electrically isolating and connecting components of gas-insulated encapsulated switching stations under, at the most, low load conditions, the fixed contact member (1) is provided with a central trailing contact (2) which ends in a contact member (7). It is coaxially surrounded by a circle of rated-current fingers (3a-h) and a fixed contact shielding electrode (15). The central contact rod (5) of the movable contact member (4) is coaxially surrounded at a distance by a shielding electrode (6) which is also movable.In order to prevent undesirable flash-overs, in particular flash-overs at the encapsulation, the rated-current fingers (3a-h) are in contact with the contact rod (5) in the area surrounded by the shielding electrode (6) which is also movable. They are mounted to be rotatable and have forces applied to them which press their end members (14a-h) radially inward.