Hitachi, Ltd.

Hitachi Electric Systems Co., Ltd.

Naoyuki Yamamoto

Koji Sasaki

Tokio Yamagiwa

Akira Suzuki

Manabu Takamoto

Toru Tsubaki

Naoki Amano

Koji Kurokawa

Noriaki Munakata

Masahiro Yaegashi

Nobuyuki Takeuchi

Kenji Iwabuchi

Osamu Tsuji

The gas-blasted circuit-breaker includes a movable arc contact, a fixed arc contact opposing the movable arc contact, an insulating nozzle, a puffer cylinder, a hollow conductor, an insulating rod connected to the puffer cylinder, and a fixed piston fitted inside the puffer cylinder. An insulating gas is ejected to a space between the puffer cylinder and the fixed piston by driving the insulating rod and is sprayed to an arc generated upon interruption of a current. The hollow conductor is in a cylindrical shape having a cross section parallel to the axis thereof. The cross section is smaller in diameter on the downstream side of a flow of insulating gas. The hollow conductor has a closed end on the downstream side of the flow of insulating gas and has a cylindrical barrel portion provided with a plurality of opening. With this configuration, this circuit-breaker ensures an operation of adjusting the flow of a heat gas, cooling of the heat gas and insulating performance for the fixed conductor to which the heat gas is sprayed.

Gas-blast circuit-breaker

A gas insulated circuit breaker includes a closed tank filled with an insulation gas, one pair of separable contacts disposed in the closed tank, a supporting frame supporting the closed tank, an opening spring for performing an opening operation of the pair of contacts, a closing spring for performing a closing operation of the pair of contacts, and an actuating mechanism box accommodating an opening coil which is adapted to receive a circuit opening command for the contacts, a closing coil which is adapted to receive a circuit closing command for the contacts and an actuating mechanism for rendering the opening spring and the closing spring operative in response to an activation of the opening coil and the closing coil. A first spring casing accommodates the opening spring and is secured on the closed tank, and a second spring casing accommodates the closing spring and is secured on the supporting frame.

Gas insulated circuit breaker

A puffer type gas-insulated circuit breaker is adapted to, when its movable electrode separates from a stationary electrode, enable an insulating gas blow toward an occurring arc to extinguish the same. An insulated nozzle is provided to direct the gas toward the arc and forms a gas passage in cooperation with an insulating cover which covers the movable electrode. The insulated cover is formed of an insulating material which contains a filler for preventing energy lines of the arc from entering the cover. Furthermore, the insulated cover has a specific inductive capacity greater than a specific inductive capacity of the insulated nozzle so as to reduce the electric field strength at the front end of the movable electrode.

Puffer type gas-insulated circuit breaker

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Hitachi, Japan

Naoyuki Yamamoto