Hitachi, Ltd.

Shigetaka Takeuchi

Takeshi Takahashi

Hideo Kawamoto

Koji Sasaki

Tokio Yamagiwa

Seizo Nakano

Satoshi Miwada

Masaki Murashita

Isao Nishida

Masayoshi Hashiura

Osamu Isshiki

Shinji Fukuda

Toshihide Mitomo

A laser welding device for welding a long sized tubular grounding unit includes a work head arranged to rotate around an outer circumference of two tubular members to be welded, a laser oscillator, and apparatus to transmit the laser beam from the oscillator in sychronism with rotation of the work head. In one embodiment the apparatus to transmit the laser beam includes an optical fiber.

Long-sized tubular grounding container unit for gas-insulated electrical

A gas insulated switchgear apparatus, in particular a phase-separated, double main bus-type switchgear apparatus, in which first and second phase-separated main buses are interchangeable and are arranged in horizontal planes in such a manner as to reduce the space needed for the apparatus.

Gas-insulated switchgear apparatus

A plurality of breaking portions forming a vertically-disposed circuit breaker are connected in series and open and close the circuit within a gas-tight sealed enclosure. The enclosure is provided at its both sides with openings for connection of one and the other ends of the breaking portions, to which openings main bus bars and an insulated-led-out device are connected, respectively. The breaking portions each have a fixed contactor and a movable contactor, and the movable contactor is put into contact with or is separated from the fixed contactor by moving the movable contactor upward or downward under control of an operating device.

Gas-insulated switchgear equipment

Growing community of inventors

Hitachi, Japan

Shigetaka Takeuchi