Hitachi, Ltd.

Fumihisa Ichikawa

Haruo Honda

Shigetoshi Ouchi

Toru Yoshida

Hideaki Tsuda

Tutomu Kanno

Yasunobu Fujita

Minoru Hosoda

Yukio Kugoh

Takashi Ichinose

Kouya Yamada

A dc power supply circuit connects a plurality of dc circuit breakers to a semi-conductor converter, returning again to the semi-conductor converter through a dc driving part such as an electric railcar connected to each dc circuit breaker. A second dc circuit breaker of larger capacity than the above-mentioned dc circuit breakers is provided in a return circuit and opened when a short circuit current is detected. A current decreasing means opens the second dc circuit breaker to decrease the short circuit current and includes, for example, a series-circuit of a resistor R and a reactor L. The dc power supply circuit has a large interruption capacity with low resistance loss.

DC power supply circuit

A commutating type DC circuit breaker arrangement comprising: a vacuum circuit breaker having a movable electrode and stationary electrode; a series circuit of a capacitor, a saturation reactor and a commutating switch which is connected in parallel with the vacuum circuit breaker; and an electrical relay for detecting a predetermined electrode open position at which a sufficient insulating distance between the movable electrode and the stationary electrode is maintained via movement of a predetermined position on an actuating rod for the movable electrode and for closing the commutating switch in response to the detection of the predetermined electrode open position.

Commutating type DC circuit breaker arrangement

Growing community of inventors

Hitachi, Japan

Fumihisa Ichikawa