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:
Sep. 10, 2002
Filed:
Oct. 27, 1998
Binish P. Desai, Secane, PA (US);
Martin J. Dowling, Norristown, PA (US);
Crane Nuclear, Inc., Kennesaw, GA (US);
Abstract
Briefly stated the motor speed monitor includes a method of determining a shaft speed of a motor by using an electrical signature of the motor. The method includes: (a) sensing an electrical current supplied to the motor to generate a current sensor output signal for at least one electrical phase of the motor; (b) demodulating the current sensor output signal for a predetermined time interval to obtain an instantaneous amplitude of the electrical current signal; (c) generating a frequency spectrum of the instantaneous current amplitude; (d) finding at least one spectral peak of the instantaneous current amplitude frequency spectrum within a predetermined shaft frequency sideband range; (e) estimating a shaft frequency from the at least one spectral peak and converting the shaft frequency to shaft speed.