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:
Feb. 13, 1990
Filed:
Dec. 05, 1988
Charles H Shin, Springfield, VA (US);
George K Woodworth, Manassas, VA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The invention finds application primarily in three phase power systems having A, B and C voltage phases. The invention includes a first voltage measurement device coupled between the A phase input and the B phase input, having a first measured voltage output. The invention further includes a second voltage measurement device coupled between the A phase input and the C phase input, having a second measured voltage output. The invention also includes a comparator having a first input connected to the first output of the first voltage measurement device and a second input connected to the second output of the second voltage measurement device, for generating a signal when the first measured voltage is equal to and opposite in polarity from the second measured voltage. This signal indicates that a zero crossover event has occurred with the A phase.