The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 19, 1996

Filed:

Dec. 19, 1994
Applicant:
Inventors:

Minoru Hosoda, Hitachi, JP;

Toru Yoshida, Hitachi, JP;

Shigetoshi Ouchi, Hitachi, JP;

Haruo Honda, Hitachi, JP;

Yasunobu Fujita, Hitachi, JP;

Fumihisa Ichikawa, Hitachi, JP;

Kouya Yamada, Hitachi, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02J / ;
U.S. Cl.
CPC ...
307 42 ; 307 11 ; 307 39 ; 335-2 ; 335-7 ; 335 18 ; 361 42 ; 361 93 ; 361139 ;
Abstract

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.


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