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:
Oct. 11, 1983
Filed:
Nov. 21, 1980
Hiroyuki Yamauchi, Saitama, JP;
Tamotsu Yamagami, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A brushless DC motor having a rotor magnet magnetized to provide a sinusoidal magnetic field and two-phase stator windings at positions which differ from each other by an electrical angle which is an odd multiple of 90.degree. is provided with a drive circuit comprising a signal generator with an output having a frequency determined by the rotational speed of the rotor, and a memory having stored therein digital information data converted from sampled values of a sinusoidal signal free of distortion. The digital information data stored in the memory is read out therefrom by the output of the signal generator in synchronism with the magnetic field from the rotor magnet, and such read-out information data is employed to determine currents flowing through the stator windings so that torque ripple is substantially eliminated.