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:
Jun. 23, 1992

Filed:

Aug. 17, 1990
Applicant:
Inventors:

Kazuhiro Ishii, Fukuyama, JP;

Kouji Hirotsune, Fukuyama, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361 93 ; 361 42 ; 361 45 ; 361 94 ;
Abstract

A current of an alternating current electric line is detected by a current transformer, the output of the current transformer is rectified by a rectifier, a series connection of a switching means and a resistor is coupled across the output terminals of the rectifier, a control circuit composed of a capacitor, a comparator and a reference voltage generator is coupled in parallel to the switching means through a diode, when the DC output voltage exceeds a predetermined voltage based on the reference voltage of the reference voltage generator, the comparator outputs a signal for closing the switching means, and the voltage which is applied to the control circuit is limited to a predetermined value.


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