Abstract: A method for testing high-voltage alternating-current power switches in a synthetic test circuit has the step of connecting a high-voltage oscillating circuit in parallel to a test switch Bt in a time interval before the current zero of an interruptible high current, which is determined by a half-cycle duration (Th/2) of the oscillating current (ih) less the duration of equivalence (?tse) of the sole flow of the oscillating current as sequential current in the test switch with a stress exerted upon the switch by the homogeneous current in a direct test circuit. The sequential-current flow duration of the equivalence results, at least approximately, from the comparison of the values of common physical stress parameters acting in the test switch during the test, on the one hand, in the synthetic test circuit and, on the other hand, in the direct test circuit.

Abstract: A method for testing high-voltage alternating-current power switches in a synthetic test circuit has the step of connecting a high-voltage oscillating circuit in parallel to a test switch Bt in a time interval before the current zero of an interruptible high current, which is determined by a half-cycle duration (Th/2) of the oscillating current (ih) less the duration of equivalence (&Dgr;tse) of the sole flow of the oscillating current as sequential current in the test switch with a stress exerted upon the switch by the homogeneous current in a direct test circuit. The sequential-current flow duration of the equivalence results, at least approximately, from the comparison of the values of common physical stress parameters acting in the test switch during the test, on the one hand, in the synthetic test circuit and, on the other hand, in the direct test circuit.

Abstract: A high-voltage oscillating circuit (I) is connected in parallel with an auxiliary circuit-breaker (Ba) by firing a switching spark gap (SGhv) and the oscillating current (ihv) is superimposed on the high-current (ihc) with opposite polarity just before the high-current zero crossing. The spark gap (SGhc) is fired at the artificial current zero, causing: short-circuiting of the high-current source (a), series connection of the high-voltage oscillating circuit with the test circuit-breaker (Bt), oscillating current from the auxiliary circuit-breaker is transferred with constant parameters to the test circuit-breaker there—in following the eliminated high current. Transient high voltage follows the zero crossing of the synthetic current continuously.

Abstract: To generate a transient high voltage, which continuously follows the zero crossing of the high-current in the test circuit-breaker, on a test circuit-breaker arranged initially in a high-current circuit, by means of a high-voltage oscillating circuit and by transferring oscillating current with constant parameters from an auxiliary circuit-breaker in the high-current circuit as sequence current to the test circuit-breaker, which is consequently located in the high-voltage oscillating circuit. A high-voltage oscillating circuit (I), connected in parallel with the auxiliary circuit-breaker (Ba) by firing the switching spark gap (SGhv) and the oscillating current (ihv) superimposed on the high-current (ihc) with opposite polarity just before the high-current zero crossing.

Abstract: A vacuum circuit-breaker contact arrangement includes a pair of contacts each being relatively axially movable from a position of engagement to a position of disengagement to establish a circuit interrupting arc therebetween, at least one of said contacts being provided with a generally cup shaped member having a base portion and a wall portion, a plurality of slots which produce winding sections being arranged in said cup shaped member, the inside of the cup shaped member being at least partly covered by a contact- and electrode-member mounted at a front side of the cup shaped member and facing the other contact, the other contact having a contact- and arc-carrying-member generally aligned with the contact- and electrode-member of the at least one contact, wherein the plurality of slots includes at least one first slot and a second slot, the base portion of at least one contact being provided with at least one first slot which essentially extends along a part of a circle and penetrates at least partly the ba

Abstract: In a dual-gas-blast puffer-type circuit-breaker a fixed insulating nozzle body (4) is integrated into a fixed insulating piston (10), forming thus a structural component. Said structural component is mounted on a fixed cylinder (11). Up to the large inner diameter of the latter the nozzle contour may expand freely, allowing thus a more effective removal of the arc plasma from the nozzle region.This feature facilitates interrupting the arc by increasing the cooling rate of the gas flow past the arc.The movable arc contact piece (17) is provided with a conical transition member between the nozzle shaped inlet side and the cylindrical base (16). That conical transition member is working like a movable piston exposed to the downstream gas flow pressure. Thus at least partly a selfcompensation of the increased gas pressure on the compression cylinder takes place in cases where large short circuit-currents are to be interrupted. This feature represents the precondition for a simple and thus reliable drive.

Abstract: A gas-blast puffer type SF.sub.6 circuit-breaker exhibiting essentially features as follows:Dual-blast nozzle arrangement wherein a first nozzle being made of electrically conductive material, and a second nozzle being made of electrically insulating material;a movable compression cylinder of electrically insulating material bearing a tube-shaped contact piece intended for carrying mainly continuous current;a nozzle-shaped arcing contact piece connected mechanically rigid and electrically suitable for carrying current with said movable contact piece.

Abstract: An improved synthetic testing arrangement for use in testing a tripolar high voltage circuit breaker wherein the arrangement includes a three-phase high-current source for impressing on the three poles of the breaker breaking currents and arc reactions and a high-voltage load for loading the pole quenching first and the remaining two poles quenching last. In accordance with the invention, the improvement comprises the further provision in such an arrangement of first and second high-voltage sources for influencing the high-voltage load and a switch means for causing the first and second high-voltage sources to be connected into the circuits formed by the three-phase current source and the circuit breaker during a breaking action; the first voltage source being connected so as to load the pole quenching first and the second voltage source so as to load remaining two poles quenching last.

Abstract: A synthetic test circuit for testing a metal-encapsulated high voltage circuit breaker of a type which is grounded on one side and which includes several switching gaps arranged in series. The testing circuit includes a high voltage source and a high current source for stressing the switching gaps during testing and, in addition, a high voltage means for applying a high voltage to the encapsulation simultaneously with the application thereto of a further voltage from the high voltage source. The high voltage is chosen to be of opposite polarity to the further voltage and the encapsulation is insulated from ground potential during application thereof.