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:
Jan. 03, 1995
Filed:
Apr. 02, 1993
Takashi Sato, Hitachi, JP;
Yukio Kurosawa, Hitachi, JP;
Kouji Suzuki, Takahagi, JP;
Akira Hashimoto, Hitachi, JP;
Shunkichi Endoo, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A vacuum circuit breaker comprising an external coil which is arranged outside a vacuum interrupter, and a power supply circuit which causes current to flow through the external coil. An overcurrent flowing through the main circuit of the circuit breaker, which leads to a load, is detected by an overcurrent tripping device so as to separate the movable electrode of the vacuum interrupter from the fixed electrode thereof and to subject a striking electric arc to a magnetic flux generated axially of the vacuum interrupter by the electrodes themselves. Thereafter, a trigger gap is ignited by a signal delivered from the overcurrent tripping device, so as to introduce a reverse current into the vacuum interrupter. Herein, the trigger gap is ignited by a signal delivered from the overcurrent tripping device, in order that the zero point of currents may be formed at the point of time at which the axial magnetic flux has been canceled by the resulting current of the external coil. Since the axial magnetic flux remaining at the zero point of the currents is nullified, charged particles are not hindered from diffusing radially of the vacuum interrupter, and hence, an enhanced breaking performance is attained.