Mitsubishi Denki Kabushiki Kaisha

Yoshiki Hirano

Mikio Hidaka

Toshiaki Yoshizumi

Daisuke Yoshida

Hiroyuki Sasao

Katsuhiko Horinouchi

Haruhiko Kohyama

Suenobu Hamano

Naoyuki Nakatsukasa

Mikio Mori

Masashi Matsuki

Kouichirou Wada

Toru Yamashita

A main circuit portions are arranged in the order of a breaking section fixed-side conductor, a breaking section movable-side conductor, a disconnecting section movable-side conductor, and a disconnecting section fixed-side conductor, and first and second grounding conductors are respectively provided for grounding the breaking section fixed-side conductor and the disconnecting section fixed-side conductor at both end portions of the apparatus. The arrangement of operating devices is set in the order of a first grounding-section operating device, a breaking-section operating device, a disconnecting-section operating device, and a second grounding-section operating device. In addition, a breaking section is supported by a single supporting insulator to reduce the number of creepage insulation portions.

Main circuit switching apparatus

A switch for use in electric power includes a fixed contact, a moving contact performing a switching operation with respect to the fixed contact, a cylinder working with the moving contact, a piston slidably provided in the cylinder, a buffer chamber which is surrounded by the cylinder and the piston, and is filled with an arc-extinguishing gas, and a second insulating nozzle mounted to an end of the cylinder on the side of the fixed contact, wherein the arc-extinguishing gas in the buffer chamber is sprayed through the nozzle on an arc generating between the fixed contact and the moving contact at an opening time of the moving contact.

Switch

In a closing operation of a circuit breaker with resistor contact, a resister contact is closed prior to closing of a main contact by the same first hydraulic operation system. In opening operation, the resistor contact is driven by a second hydraulic operation system used to close the main contact after operating the main contact by the first hydraulic operation system. Opening timing of the resistor contact is controlled by a mechanical interlock mechanism or hydraulic control circuit.

Circuit breaker

A double-break type circuit breaker includes two resistor contacts which are to be connected in parallel with respectively two main contacts when the main contacts are closed. An engagement mechanism is provided for linking the main contacts operated by a first hydraulic operation apparatus and the resistor contacts operated by a second hydraulic operation apparatus.

In a driving mechanism of a circuit breaker having first and second hydraulic operation apparatuses respectively driving a main contact and a resistor contact, a sequential control valve is provided between the first and second hydraulic operation apparatuses. The sequential control valve detects the operation of a differential piston for opening the main contact and switching the differential piston for sequentially opening the resistor contact after the opening of the main contact.

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Amagasaki, Japan

Yoshiki Hirano