Patent ID: 7683507
Filing Date: 2010-03-23
Classification: H02K

Abstract:
1. A linear generator having an annular armature and a translator located concentrically therethrough and which are movable relative to one another along a longitudinal axis, wherein a magnetically permeable sleeve is affixed to and circumferentially surrounds the armature, the permeability of one or both ends of the sleeve being contoured around its circumference such that the variation of the longitudinal cogging force on the sleeve in its travel with the armature relative to the translator is reduced, wherein said contouring of the permeability is achieved by a variation in the amount of material around the circumference of the sleeve end at one or both ends of the sleeve, such variation being in the form of varying absence of sleeve material at locations around the circumference of the armature, and wherein the sleeve includes or is constructed from a multiplicity of individual ferromagnetic elements for drawing out lines of flux from the translator, but each being of a shape and individually insulated such as to eliminate substantially the circulation of eddy currents around and/or along the circumference of the sleeve.