Hitachi, Ltd.

Hiromichi Hokutou

Akira Suzuki

Masatomo Ohno

Tetsuo Fukuchi

A gas-filled circuit breaker includes a hermetically sealed tank formed by a surrounding wall filled with an insulating gas, at least one pair of contacts which are arranged in the inside of the surrounding wall, and a contact operating device for connecting the contacts to each other for conducting electricity therebetween and separating the contacts from each other for interrupting the electricity therebetween. The contact operating device includes a force generating device for generating a force for operating the contacts, and the contact operating device is arranged outside of the surrounding wall. A rotational shaft device is connected to the force generating device outside of the surrounding wall and extends from the outside of the surrounding wall to the inside thereof so that the force generated by the force generating device is transmitted through the surrounding wall to the inside thereof. A seal device is arranged between the surrounding wall and the rotational shaft device to maintain a hermetic seal therebetween, and at least two bearings rotatably support the rotational shaft device; and a connecting device for transmitting the force from the rotational shaft device to at least one of the contacts is moved in relation to another one of the contacts, wherein the connecting device is connected to the rotational shaft device between the bearings.

Operating mechanism for an inert gas filled circuit breaker

An operating device for a gas circuit breaker includes an operating piston reciprocably movable between a first position and a second position, with the operating piston dividing an internal space of the operating cylinder into a first chamber and a second chamber. An exhaust port in the operating cylinder communicates with the first chamber when the operating piston is disposed near the second position, and the exhaust port communicates with the second chamber when the operating piston is remote from the second position. High-pressure air is introduced into the first chamber at the time of the breaking operation. An exhaust valve device discharges the air from the first chamber when the air pressure within the first chamber decreases below a predetermined level. The exhaust valve device includes a valve element having a pressure-receiving portion receiving the air pressure from the first chamber. The pressure-receiving portion is positioned so as to be out of contact with the operating piston when the operating piston is disposed at the first position.

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Hitachi, Japan

Hiromichi Hokutou