Abstract: The current-limiting resistor has two connection electrodes (1, 2) which are arranged parallel to one another as well as a resistance body (3) which has PTC behavior and with which large-area contact is made by the connection electrodes (1, 2). A varistor (40) is in electrically conductive contact with the resistance body (3). The resistance body (3) contains two contact areas (50, 51) as well as a response point (60) which is connected in parallel with the varistor (40) via the two contact areas (50, 51) and implements a PTC transition above a threshold value of a current flowing through the resistor.Since the resistance body effects the electrical contact with the varistor (40) in the case of this resistor, no metal connection electrodes are required for the varistor. At the same time, due to the outward displacement of the response point (60) away from the varistor (40), the operational reliability of the resistor is considerably improved.

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 high-voltage switch filled with an insulating medium has at least one interrupter chamber (3, 3a) fixed on a central housing (2) supported by an insulator column (1). Fitted in the region of the at least one interrupter chamber (3, 3a) is at least one measuring head (6), in which a sensor (9) picks up current-proportional measuring signals. These measuring signals are transmitted via an optical waveguide (16) at ground potential for further processing.A high-voltage switch is to be created in which sensors (9, 39) can be fitted by simple means in easily accessible manner outside in the region of the interrupter chamber (3, 3a). This is achieved by the at least one measuring head (6) being accommodated in a housing suitable for fitting outside on the high-voltage switch. In this arrangement, the optical waveguide (16) is led pressure-tight through a closure cover (38) of a fitting opening into the central housing (2).

Abstract: A gas-blast switch, preferably suitable for switching high voltages, has two arc contacts which can be moved relatively to each other along an axis. Also included are a heating volume and a compression volume concentrically formed around the axis. Quenching gas is compressed in the compression volume by means of a compression slider. As soon as the gas pressure is sufficiently high, a part of the quenching gas flows via a back-pressure valve into the heating volume and there assists in blasting an arc drawn between the arc contacts during a switching-off process. The assist is needed primarily when only small currents are involved in which case only comparatively low quenching gas pressure is developed in the heating volume. The switching-off capacity of the gas-blast switch is increased with simultaneous reduction in the needed actuating energy.

Abstract: An electric switch having contact elements designed in the form of contact pins is disclosed. Contact pins and flat springs are arranged in units, each unit having a contact pin and an associated flat spring, and each unit extending in the make/break direction of the switch. Each contact pin-flat spring unit is held between a contact carrier and a cage. The cage may be held in place by outer ends of the flat springs. A tubular conductor or a contact blade can be used as a mating contact. The mating contact is in electrical connection with the contact pins when the switch is in the make position. The individual contact elements can be easily replaced, and a standard design contact element can be used in switches of various sizes and types. A switch according to the present invention is particularly suitable for use with large surge currents.

Abstract: The invention relates to a combined current and voltage converter for metal-enclosed high-voltage installations with compressed-gas filling. In order to be able to avoid any passages for the connecting leads through the housing (1, 2), the electrode of the capacitive voltage converter part consists of an intermediate element (3) inserted into the housing in an insulated and gas pressure-tight manner. The intermediate element (3) has on its outside a layer of insulating material (9) and on top of this a metal layer (10). The whole (3, 9, 10) forms a support body for current converter cores (11) surrounded by secondary windings. The low-voltage capacity between the intermediate element (3) and the metal layer (10) is fed to an electronic measuring amplifier (14) via a screened measuring cable (12/12a). The current converter cores (11) are protected mechanically by a sheath tube (16), the latter simultaneously conducting housing currents. FIG. 1.

Abstract: A partition insulator is disclosed having a seating in at least one insulator holder. A specific predetermined rupture behavior is provided for the partition insulator as a result of outside forces acting on the insulator at a specific quantity and direction such as, for example, gas pressure. A corresponding support (or gripping or solid gripping) of the partition insulator is provided whereby at least on the insulator, on the insulator holder or between these two parts, bearing points (or bearings) are arranged in a suitably distributed manner. The gripping of the partition insulator is accomplished herewith by the insulator holder alone or by both the insulator holder and a fastening ring which holds the partition insulator together by both threaded bolts and nuts. The partition insulator is preferably used as a pressure relief device in pressurized gas-insulated high-voltage switchgears having a metal switchgear casing.

Abstract: An electrical switch is provided with at least one set of stationary and movable main contacts for opening and closing the circuit controlled by it, and a set of stationary and movable auxiliary contacts for connecting a resistor in parallel with the main contacts and hence into the circuit controlled by the switch during a switching-in operation prior to engagement of the main contacts. The resistor is then disconnected either after the main contacts have engaged, or it is disconnected later during a switching-out operation prior to dis-engagement of the main contacts. Both operational modes are effected by means of a follower device which couples the movable auxiliary contact with the movable main contact.

Abstract: A structural component such as nozzle-forming member to be utilized in conjunction with the arc quenching chamber of an electrical circuit breaker operating with a pressurized gaseous fluid such as SF.sub.6 and made from a polytetrafluoroethylene composition that is gas-emissive under influence of heat generated by the arc in the vicinity of the nozzle is provided with a system of gas-conducting passageways to permit such gas to escape from sub-surface cavities formed by deterioration of the composition rather than accumulate therein which leads ultimately to undersirable chipping off of pieces of the surface. These passageways may be constituted by a system of blind holes or by a system of grooves.