Hitachi, Ltd.

Nec Electronics Corporation

Naoki Kawamura

Masato Suzuki

Yoshihiko Matsuda

Noriaki Munakata

Manaba Takamoto

Masaru Haga

A commutation type DC breaker comprising a main switch inserted in series into a main circuit for connecting a DC source and a load, a commutation capacitor, a reactor, and a commutation switch for supplying charges stored in the commutation capacitor to the main switch in an opposite direction to a main circuit current, producing a current zero point, thereby breaking the main switch,

Commutation type DC breaker

A DC switchgear is provided with a commutation-type DC circuit breaker having a main circuit provided with a main switch for interconnecting a DC power supply and a load, and a commutating circuit provided with a commutating capacitor and a commutating switch, which is connected electrically parallel to the main switch. The switchgear further has a DC circuit breaker accommodating box that includes the main circuit provided with the main switch, and the commutation-type DC circuit breaker; a front accommodating box disposed on the front of the DC circuit breaker accommodating box, which accommodates devices having functions for controlling the switchgear and indicating a status, such as a failure status thereof; and a rear accommodating box disposed on the back of the DC circuit breaker accommodating box. The front and rear accommodating boxes are connected to the DC circuit breaker accommodating box to form an integrated DC switchgear.

DC switchgear provided with a commutation-type DC circuit breaker

A method for the computation of a system processing time in performing an operation in a system which can process a plurality of lots in a continuous or parallel manner, wherein the processing time of an object lot is computed based on the minimum processing time Sfor the object lot, the contents of the operation of a lot which is currently being processed, and the actual processing time of a lot, for which the operation has recently been completed.

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Hitachinaka, Japan

Naoki Kawamura