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:
Jul. 25, 1995
Filed:
Sep. 24, 1993
Applicant:
Inventors:
Marc Ferrazzi, Fontaine, FR;
Alain Del Vecchio, Echirolles, FR;
Assignee:
Merlin Gerin, , FR;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361 42 ; 361 45 ; 361 93 ;
Abstract
An electronic trip device comprising, for each phase or neutral line, a rectifier bridge formed by four diodes which rectify the transformer current, a resistance for measuring the rectified current, and a circuit for detecting the sign or polarity of the measured current connected to one end of the transformer. A processing circuit calculates a value representative of the earth fault current by adding all the current values whose corresponding sign is positive and subtracting all the current values whose corresponding sign is negative. This current value is processed so as to bring about tripping when a threshold is exceeded for a preset time.