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, 1990
Filed:
Dec. 22, 1988
Harold B Harms, Fort Wayne, IN (US);
Ronald J Krefta, Fort Wayne, IN (US);
John L Oldenkamp, Fort Wayne, IN (US);
General Electric Company, Fort Wayne, IN (US);
Abstract
An electronically commutated motor has substantially constant air gap energy to reduce cogging. A rotatable assembly has permanent magnet elements which rotate about an axis of rotation. The elements are oriented with respect to said axis of rotation to provide a magnetic field with lines of flux along a plane forming a skew angle of s.sub.1 mechanical degrees with respect to the axis of rotation, wherein s.sub.1 is not equal to zero. The elements may be provided with an unmagnetized portion referred to as a phantom skew. A stationary assembly is in magnetic coupling relation with the permanent magnet elements of the rotatable assembly and has t spaced teeth with adjacent teeth defining a slot therebetween, wherein t is positive integer. Each tooth has a surface adjacent the rotatable assembly having one or more notches forming a skew angle of s.sub.2 mechanical degrees with the axis of rotation. Each tooth has winding stages adapted for commutation in at least one preselected sequence. The skewed magnetic field, skewed notches and phantom magnetic skews reduce cogging between the rotatable assembly and the stationary assembly as the rotatable assembly rotates, while maintaining a back EMF waveform having a maximized flat top width.