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:
Sep. 26, 1989
Filed:
Apr. 19, 1988
Masayasu Kurono, Aichi, JP;
Ryoichi Unno, Aichi, JP;
Yukiharu Matsumoto, Aichi, JP;
Yasuaki Kondo, Aichi, JP;
Takahiko Mitani, Aichi, JP;
Takahito Jomori, Aichi, JP;
Hisashi Michishita, Aichi, JP;
Kiichi Sawai, Aichi, JP;
Sanwa Kagaku Kenkyusho Co., Ltd., Aichi, JP;
Abstract
A removable rating plug for a circuit breaker provides an active variable impedance in series with a reference resistor between the sensing terminals of the circuit breaker trip circuit to adjust the sensing voltage produced in response to the input current received from current monitors in the protected circuit. The active variable impedance, which is energized by the input current, includes a high gain transistor amplifier, preferably a Darlington transistor, controlled by an operational amplifier. A control circuit includes a pair of reference diodes which match the forward drop across the Darlington transistor when full on, in series with a reference voltage selection circuit which applies a reference voltage to the non-inverting input of the operational amplifier. The voltage at the connection between the Darlington transistor and the reference resistor is fed back to the inverting input of the operational amplifier so that the gain of the amplifier, and therefore the variable impedance in series with the reference resistor, varies with the reference voltage.