US 7,009,319 B2Granted

Controlling electric motor cogging

AssigneeEmerson Electric Co.

InventorRichard E. Hartsfield, Jr.

Life of this patent

Estimating the term…

Abstract

A method of determining magnet pole geometry for controlling cogging in an electric motor includes defining the magnet pole geometry in terms of at least one design parameter, predicting cogging as a function of the design parameter, and from the predicted cogging, selecting a value for the design parameter which corresponds to a desired level of cogging in the electric motor.

Claims5

Dependent claims

A rotor for an electric motor, the rotor having a diameter and comprising a plurality of permanent magnets, each of the permanent magnets having a magnet decenter radius value Rmo and a magnet pole span value Bm, wherein:

Bm=6n+π(Rmo/Rad1)2−(7π/3)*(Rmo/Rad1)+(5π/3)±1 mechanical degree, Rad1 is the diameter of the rotor, and n is an integer greater than one.

Dependencies are inferred from the claim text.

Facts

Application: 10/872,751Filed 21 Jun 2004 · division
Priority: 7 Jan 2003
Published: US 2005/0040722 A124 Feb 2005
Granted: 7 Mar 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H02K 1/278
The rotor consisting of magnets or groups of magnets arranged with alternating polarity: surface mounted magnets; Inset magnets
H02K 15/00
Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of
H02K 15/03
Of stator or rotor bodies: having permanent magnets
H02K 21/16
With magnets rotating within the armatures: having annular armature cores with salient poles

Family

Application10/337,835Parent of this division · filed 7 Jan 2003
US 2005/0040722 A1Pre-grant publication · published 24 Feb 2005
US 6,753,632 B1Parent of this division
US 7,009,319 B2This patent

From the US filing history. Foreign family members aren’t listed.

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