Patent ID: 7307366

Claim:
An electrical machine comprising: a stator including a stator core and windings; a rotor including one or more permanent magnets adapted to interact with the stator to promote rotation of the rotor about an axis, each permanent magnet being configured to include at least four axial sections having a magnetization pattern of alternating magnetic poles that are skewed with respect to the axis along substantially straight lines, the at least four axial sections including a first axial section having a first magnetization direction, having a first axial length, and having an arc of magnetization skew (β), a second axial section disposed adjacent to the first axial section, the second axial section having a second magnetization direction that is different from the first axial section, having a second axial length, and having the arc of magnetization skew (β), a third axial section disposed adjacent to the first axial section, the third axial section having a third magnetization direction that is different from the first magnetization direction, having a third axial length, and having the arc of magnetization skew (β), a fourth axial section disposed adjacent to the second axial section, the fourth axial section having a fourth magnetization direction that is different from the second magnetization direction, having a fourth axial length, and having the arc of magnetization skew (β); and wherein the first, second, third, and fourth magnetization directions define a continuous zig-zag pattern in the axial direction.