Mitsubishi Denki Kabushiki Kaisha

Toshimasa Maruyama

Kenichi Koyama

Hiroyuki Sasao

Yukimori Kishida

Yuichi Yamaji

Kazuhiko Nishimiya

Hiroshi Yamamoto

Masakazu Fukada

Hiroshi Hasegawa

Minoru Kobayashi

Junichiro Nishitani

Toshifumi Sato

In a switchgear, by using a spring with a varying spring constant from closing to electrode opening as a loading spring, spring load in the opened electrode state is made smaller than a spring load in the closed electrode state to decrease the energy required from electrode closing up to electrode opening. Moreover, by using a spring in which a load in the opposite direction to a load in the closed electrode state works in the opened electrode state, the opened electrode state can be held securely.

Switchgear

A fast changeover from one power system to another in the event of an irregularity in the power source system substantially reduces operating costs by minimizing a power loss in switches during conduction, dispenses with a cooling device for cooling a thyristor switch, and implements the thyristor switch in a compact and low-cost design. The power supply system for a load includes one switching apparatus for connecting a load to one power source system, and another switching apparatus for connecting the load to another power source system. Each of the switching apparatus includes a pair of thyristors connected in anti-parallel and a mechanical switch connected in parallel with the thyristor pair. The thyristor pairs and the mechanical switches are controlled so that the mechanical switches conduct a load current when the load is supplied with power from the one power source system in a steady power supply state. The thyristor switches conduct the load current during a power source changeover time within which the load is disconnected from one power source system and connected to the other power source system, and do not conduct the load current during the steady power supply state.

Electric power supply system for load

An insulative tube (93) of a switch is molded with an inserted tubular condutor (15), and a sliding contact (14) provided on outer surface of a piston (7) slides on an inner surface of the tubular conductor (15); the insulative tube (3) is thereby reinforced against the pressure of an insulation gas sealed in the insulative tube (3). The piston (7) and the tubular conductor (15) are electrically connected in a stable manner and undesirable tottering of moving contacts (8), (16) mounted on the piston (7) can be prevented.

Arc-extinguisher of a switch

Growing community of inventors

Tokyo, Japan

Toshimasa Maruyama