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.
Patent No.:
Date of Patent:
May. 25, 1993
Filed:
Jul. 31, 1990
Mitsuyoshi Hasegawa, Katsuta, JP;
Takashi Tsuboi, Katsuta, JP;
Hiroyuki Akiyama, Katsuta, JP;
Tadashi Kamada, Katsuta, JP;
Taro Uchii, Katsuta, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A vacuum circuit breaker particularly suitable for use in an electric motor vehicle. The circuit breaker includes a vacuum interrupter to which a voltage is applied, the series combination of a capacitor and a switch which are connected in parallel with the vacuum interrupter, a provision for charging the capacitor with a voltage opposite the voltage applied to the vacuum interrupter, and a resistance connected in parallel with the vacuum interrupter. The vacuum interrupter, the resistance, and the series combination of the capacitor and switch form oscillation circuit having an oscillation frequency at least 2 KHz and an inductance of at least 1 .mu.H, with a commutating current of at least 5000 A for consuming energy stored in the circuit. In one embodiment, a capacitive element is connected in parallel with the resistor, and the length of the closed circuit include the vacuum interrupter and the capacitive element is shorter than the length of the closed circuit including the vacuum interrupter, the first capacitor, and the switch. Likewise, where no capacitive element is included, the length of the closed circuit including the vacuum interrupter and the resistance is shorter than the length of the closed circuit including the vacuum interruptor, the capacitor, and the switch. The resistance can be a linear or a nonlinear resistor, or the parallel combination of a linear resistor and a nonlinear resistor.