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. 01, 1990
Filed:
Apr. 12, 1989
Edward R O'Brien, III, Wayne, PA (US);
SPD Technologies Inc., Philadelphia, PA (US);
Abstract
Apparatus for detecting a primary fault current in a three-phase current system and converting the detected fault current in the mechanical action for breaking a circuit in which the primary fault current occurred includes a combination of transformers and diodes for receiving the three phases of current, providing corresponding phases of secondary current within a predetermined desired amperage metering range, choosing the largest magnitude secondary current and providing the largest magnitude secondary current as output, a resistor for providing voltage proportional to the largest magnitude secondary current, a capacitor for storing a peak value of the voltage which is proportional to the largest magnitude secondary current and a latching circuit for moving a trip member and providing mechanical action in response to the largest magnitude secondary current exceeding a predetermined level.