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:
Jun. 12, 1984
Filed:
Jul. 22, 1981
Donald S Kimmel, Monroeville, PA (US);
William H South, McKeesport, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
Signal conditioning apparatus for reducing the noise frequencies of a speed sensing means signal being fed into a compensating means for compensating the output of a synchronous generator for the effect of torsional oscillation between masses in the main AC generator system. The signal conditioning apparatus includes two speed sensing transducers mounted 180.degree. apart on opposite sides of a tooth gear wheel and summing the two FM output signals from the transducers to eliminate odd harmonics of the synchronous frequency in FM noise due to eccentricity. The preferred embodiment of the invention reduces the remaining noise from the sensed speed signal by the use of a three-pole Butterworth low-pass filter in combination with a notch filter tuned to the turbine-generator synchronous frequency to thereby reduce the unwanted noise to a large degree while providing a minimal phase shift to the sensed speed signal. Another embodiment of the invention may be used to determine the machining accuracy of the toothed gear wheel.