Tokyo Shibaura Denki Kabushiki Kaisha

Kabushiki Kaisha Toshiba

Takumi Funahashi

Satoru Yanabu

Tohoru Tamagawa

Eiji Kaneko

Mitsutaka Homma

Tohru Tamagawa

Hiroyuki Okumura

Koichi Yasuoka

Shigeo Souma

A vacuum switch having two main electrodes encased in a vacuum vessel to be operable in opening and closing the main electrodes, is provided with a contact piece made of a copper-chromium alloy secured or formed on at least one of the main electrodes. The operational property of the main electrodes is substantially improved by flowing and interrupting an electric current of a predetermined current density for a number of times through the two main electrodes for improving surface condition of the contact piece by forming a recrystallized layer over the outer surface of the contact piece.

Method for processing vacuum switch and vacuum switch processed by the

A DC circuit breaker of the type using a blown arc-extinguishing gas is disclosed which allows for reliable fast interruption of DC currents through the provision of arc extension current paths. The extension current paths are relatively long and are bent after the incidence of the arc-extinguishing gas on the arc. The arc is formed to extend for a long distance in a loop configuration. An auxiliary electrode short-circuits the extended arc with one auxiliary electrode being provided for each extension current path.

DC Circuit breaker

A DC circuit breaker apparatus comprises a first interrupter and a second interrupter connected in series. A first capacitor and a discharge gap are respectively connected in parallel with the first and second interrupters. An impedance element is connected between a first junction between the first capacitor and the discharge gap and a second function between the first and second interrupter, and a second capacitor is connected in parallel with the second interrupter.

DC Circuit breaker apparatus

In a vacuum interrupter of the type comprising a vacuum vessel and a pair of separable main electrodes located in the vacuum vessel, at least one of the main electrodes being provided with a coil electrode for generating an axial magnetic field, the vacuum interrupter further comprises a flat annular intermediate electrode disposed between the main electrodes and provided with an opening at its center through which one of the main electrodes passes.

Growing community of inventors

Yokohama, Japan

Takumi Funahashi