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:
Nov. 23, 1976
Filed:
Apr. 08, 1975
Applicant:
Inventor:
John K Penrod, Bellbrook, OH (US);
Assignee:
Power Management Corporation, Dayton, OH (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
3402 / ; 324 / ; 324 / ; 324 / ; 324186 ; 307234 ; 328134 ;
Abstract
A method and apparatus for detecting an underfrequency condition of an alternating current power line is disclosed wherein the frequency of the power line is sensed, an underfrequency signal is developed whenever the power line frequency decreases below a predetermined frequency, a known frequency source is thereafter substituted for the alternating current power line, and the frequency of this source is checked by the same circuitry to produce a second output signal, and an underfrequency signal is generated in response to both first and second output signals.