Rotor-stator structure for electrodynamic machines

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Definitions The following definitions apply to some of the elements described with respect to some embodiments of the invention.
These definitions may likewise be expanded upon herein.
As used herein, the term "air gap" refers to a space, or a gap, between a magnet surface and a confronting pole face.
Such a space can be physically described as a volume bounded at least by the areas of the magnet surface and the pole face.
An air gap functions to enable relative rotation between a rotor and a stator, and to define a flux interaction region.
Although an air gap is typically filled with air, it need not be so limiting.
As used herein, the term "back-iron" commonly describes a physical structure (as well as the materials giving rise to that physical structure) that is often used to complete an otherwise open magnetic circuit.
In particular, back-iron structures are generally used only to transfer magnetic flux from one magnetic circuit element to another, such as either from one magnetically permeable field pole member to another, or from a magnet pole of a first magnet to a magnet pole of a second magnet, or both, without an intervening ampere-turn generating element, such as coil, between the field pole members or the magnet poles.
Furthermore, back-iron structures are not generally formed to accept an associated ampere-turn generating element, such as one or more coils.
As used herein, the term "coil" refers to an assemblage of successive convolutions of a conductor arranged to inductively couple to a magnetically permeable material to produce magnetic flux.
In some embodiments, the term "coil" can be described as a "winding" or a "coil winding.
" As used herein, the term "coil region" refers generally to a portion of a field pole member around which a coil is wound.
As used herein, the term "core" refers to a portion of a field pole member where a coil is normally disposed between pole shoes and is generally composed of a magnetically permeable material for providing a part of a magnetic flux path