Hitachi, Ltd.

Other

Hitachi Electric Systems Co., Ltd.

Haruo Honda

Takahide Seki

Shigetoshi Ouchi

Toru Yoshida

Yukio Kurosawa

Tohru Tsubaki

Noriaki Munakata

Shigetoshi Oouchi

Syunji Itoh

Tutomu Kanno

Masaki Shinohara

Yukio Kugoh

Fumihisa Ichikawa

Takeshi Takahashi

Masanori Tsukushi

Yasuharu Seki

Syunji Itou

Masabumi Oshima

Yasunobu Fujita

Hideaki Tsuda

Hiroshi Itoh

Minoru Hosoda

Shigeru Fujiya

Mitsuga Haginoya

Shinichi Ohde

Takashi Ichinose

Kouya Yamada

A power use circuit breaker includes an arc generating switching unit which adds an electrical resistance in a circuit during current interruption to attenuate a current to be interrupted, a vacuum bulb which is electrically connected in series with the arc generating switching unit and interrupts the attenuated current and a current conducting switching unit connected in parallel with the series circuit of the vacuum bulb and the arc generating switching unit. For current conduction the current conducting switching unit is closed after the vacuum bulb and the arc generating switching unit are closed, and for current interruption after opening the current conducting switching unit, the vacuum bulb and the arc generating switching unit are opened.

Power use circuit breaker and electrical circuit arrangement for electric power generation plant

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 commutation type DC breaker having a commutation circuit electrically connected in parallel to a main contact. The main contact is connected between a DC power supply and a load. The commutation circuit is a series circuit of a commutation capacitor, a reactor and a commutation switch, with an energy absorption device electrically connected in parallel to the main contact. A switch or a breaker for preventing the flow of commutation current from the commutation circuit to the load in a non-load opening mode is connected between an electrical connection point (P), of the main contact and the commutation circuit, and the load and is opened substantially simultaneously with the opening of the main contact, or before the closure of the commutation switch. In this manner, the safety on the load in the non-load opening mode is enhanced.

Commutation type DC breaker

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

An interrupter unit comprising, an interrupter including at least two pairs of contacts, and an interrupter container surrounding the pairs of contacts, each of the pairs of contacts having a first contact and a second contact which contacts the first contact or is positioned away from the first contact so that electricity flows between the first contact and the second contact or is prevented from flowing between the first contact and the second contact, an electric actuator device for driving the pairs of contacts so that the second contacts contact the first contacts or are positioned away from the first contacts, and at least one voltage-transformer which transforms an input voltage and supplies a suitably transformed voltage to the electric actuator device so that the electric actuator device drives the pairs of contacts, wherein the interrupter unit further comprises an electrically grounded cover surrounding the interrupter and having first cover terminals which are electrically connected to the first contacts, respectively, and second cover terminals which are electrically connected to the second contacts, respectively, wherein, the electric actuator device and the voltage-transformer are located in a space formed between the electrically grounded cover and the interrupter, the voltage-transformer being electrically connected to at least one of the cover terminals of the electrically grounded cover to receive the input voltage. Therefore, the inventive interrupter unit may be smaller than a prior art interrupter unit, while maintaining the safe condition of the interrupter unit.

Interrupter having grounded interrupter container within a grounded cover

A gas-blast load-break switch comprises a pressure storage chamber for storing pressure of arc-extinguishing gas with arc energy generated by the disconnection between contacts, and a suction chamber including a piston which is moved in connection with the cut-off movement of the movable contact. A gas flowing device is provided such that the pressure raised by the arc energy is stored in the pressure storage chamber before communicating the pressure storage chamber and the suction chamber and a gas chamber formed on the opposite side of the piston from the suction chamber. The volume of the gas chamber is greater than that of the pressure storage chamber and the suction chamber, and the distance of piston movement in the suction chamber is longer than the contact length when the movable contact is thrown into the fixed contact.

Gas-blast load-break switch

A switch provided with a negative pressure chamber which is actuated in association with the separating operation of a movable contact. The negative pressure chamber is connected to a means for supplying a fluid to the negative pressure chamber so as to suppress the negative pressure in the negative pressure chamber during the initial stage of the separaating operation of the movable contact.

Switch

A gas insulated switchgear system having two gas insulated switchgear equipments, each of which consists of first disconnecting switches, circuit breakers, and second disconnecting switches, three phase gas insulated buses which are respectively connected to the first disconnecting switches of the two gas insulated switchgear equipments in every three phases thereof, a single phase reserve buses which are commonly connected to all of the second disconnecting switches of the two gas insulated switchgear equipments, and an operating device for opening the circuit breakers and the first disconnecting switches in only one phase of the gas insulated switchgear equipments and closing the second disconnecting switch in only the one phase. A gas insulated switchgear system having single phase reserve bus is economical and switches one of the three phase main buses to the single reserve bus without forming short circuit.

Gas insulated switchgear system having single phase reserve bus

A center shaft of a swing lever, connected to a moving contact of a main interrupting unit, is supported by hollow bearings. The center shaft is provided with an engaging portion which is positioned in the hollow space of the hollow bearing and therein connected to a rotating shaft of which the force is partially exerted on a moving contact of a closing resistor device. Therefore, if the gas circuit breaker does not need the closing resistor device, the rotating shaft may be removed. For the gas circuit breaker requiring the closing resistor device, the rotating shaft may be inserted into the hollow bearings. For both cases, the gas circuit breaker is thus able to take the same fundamental construction.

Gas circuit breaker

A pilot valve device adapted to be brought to an open position in response to a mechanical signal so as to cause a compressed fluid to actuate an operating valve. The pilot valve device comprises a main valve located in a pilot valve chamber, and a daughter valve located in a daughter valve chamber formed in the main valve. When a mechanical signal is applied to the daughter valve and brings the same to an open position, a compressed fluid contained in the pilot valve chamber is introduced into a main valve actuating chamber, with the result that the main valve is brought to an open position to permit the compressed fluid to flow into an operating valve actuating chamber.

Pilot valve device for regulating the flow of a fluid

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Hitachi, Japan

Haruo Honda