Granted Patent
Utility
US 4,246,623 · App. 05/940,801
Protective relay device
Inventor:
Shan C. Sun
Patented Case
View Patent ↗
Granted: Jan 20, 1981
Filed: Sep 8, 1978
Inventor
Shan C. Sun
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.