Granted Patent
Utility
US 4,743,789 · App. 07/002,732
Variable frequency drive circuit
Inventor:
William L. Puskas
Patented Case
View Patent ↗
Granted: May 10, 1988
Filed: Jan 12, 1987
Inventor
William L. Puskas
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.