Areva T&d Sa

Gec Alsthom Sa

Francois Biquez

Jean-Marc Willieme

Denis Frigiere

An alternator disconnector circuit-breaker of the invention presents a resistance () in series with the circuit-breaker switch (); the resistance () is of fixed ohmic value that is about 10times greater than the value of the resistance of the main circuit of the circuit-breaker. By means of this configuration, it is possible to use a vacuum chamber as the circuit-breaker switch (), and to dimension the main switch (), which, de facto, breaks the current even for very high short-circuit currents, under more advantageous conditions.

Alternator circuit-breaker with an inserted resistance

An alternator disconnector circuit-breaker of the invention presents a compact structure. The axes of opening/closure of the change-over first switch (), of the circuit-breaker second switch (), and of the disconnector switch () are such that an angle of 90&#xb0; is present between two of them. Actuator means () associated with synchronization means () make it possible to ensure that each switch is operated in a time-shifted manner by common control means.

Compact disconnector circuit-breaker for an alternator

A gas blast circuit breaker comprises a cylindrical metal or insulative enclosure filled with pressurized insulative gas, a fixed arc contact and a mobile assembly coupled to an operating member comprising a gas blast cylinder associated with a gas blast nozzle and cooperating with a piston, and a mobile arc contact carried by a tubular member inside the gas blast cylinder. The inside wall of the tubular member comprises a bottleneck whose cross-section is less than the inside cross-section of the tubular member and coaxial therewith. The minimum cross-section of the bottleneck has a diameter less than or equal to the diameter of the inside cross-section of the mobile arc contact and equal to at least 0.75 times the diameter of the inside cross-section of the mobile arc contact. The operation of the circuit breaker is improved by increasing the gas pressure near the mobile arc contact by virtue of a particularly simple and low-cost arrangement.

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Brignais, France

Francois Biquez