Granted Patent
Utility
US 4,675,775 · App. 06/808,769
Active pilot wire apparatus for electromechanical current differential relays
Inventors:
Shan C. Sun, Russell W. Gonnam
Patented Case
View Patent ↗
Granted: Jun 23, 1987
Filed: Dec 13, 1985
Inventors
Shan C. Sun
Russell W. Gonnam
Assignee (at issue)
Westinghouse Electric Company LLC
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.