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. 07, 2000
Filed:
Oct. 02, 1996
Daniel A Quinlan, Warren, NJ (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A method and apparatus for substantially reducing tonal noise and or vibration generated by a rotating machine. The power supplied to the rotating machine or motor drive signal is modulated as a function of time so that the shaft rate of the rotating machine is varied as a function of time. The motor drive signal or power signal can be modulated in an alternating current (AC) machine wherein the shaft rate is related to the power line frequency, as well as a direct current (DC) machine wherein the shaft rate is related to the DC level applied, to alter the shaft rate as a function of time. Such drive power modulation causes the drive signal energy to spread into new frequencies. As a result, the radiated tonal components are spread out such that the strength of the rotating machine's tonal radiation is substantially reduced. In addition, 'beating' effects related to the operation of multiple machines can be reduced.