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. 12, 1988
Filed:
Mar. 31, 1987
Applicant:
Inventor:
Edward C Prather, Hendersonville, NC (US);
Assignee:
Westinghouse Electric Corp., Pittsburgh, PA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G05B / ;
U.S. Cl.
CPC ...
318473 ; 318807 ; 318798 ; 318806 ; 361 24 ;
Abstract
A motor protection relay is taught which determines effective and RMS values of current on a cycle-by-cycle basis by measuring three-phase currents at 10.degree. intervals in a line cycle and then determining the positive and negative sequence components thereof by storing the accumulated information in a memory. In order to increase the dynamic range of the sensing apparatus, only the negative half wave of each current is sensed and the positive half wave is reconstructed by finding the 180.degree. phase shifted equivalent thereof in the negative half wave.