An interior permanent magnet motor comprising: a rotor assembly disposed within a stator assembly; the rotor assembly being configured for rotating about a central axis relatively to the stator assembly; the rotor assembly defining a plurality of magnet pockets within the rotor assembly along a radially outboard surface of the rotor assembly, each magnet pocket being substantially rectangular in cross-sectional shape, and each magnet pocket being configured to facilitate insertion of a group of permanent magnet segments into and retention of the group of permanent magnet segments within, the magnet pocket; the rotor assembly further comprising a group of permanent magnet segments disposed in each magnet pocket, the stator assembly comprising a plurality of winding posts, each having a stator tooth at a radially inward end of each of the plurality of winding posts, and each stator tooth defining an inner surface, characterized in that each inner surface consists of a leading planar stator tooth surface, an intermediate planar stator tooth surface, and a trailing planar stator tooth surface, wherein the leading planar stator tooth surface and the trailing planar stator tooth surface are angled toward the central axis with respect to the intermediate planar stator tooth surface, and wherein a leading chord length of the leading planar stator tooth surface is substantially equal to a trailing chord length of the trailing planar stator tooth surface, and an intermediate chord length of the intermediate planar stator tooth surface is equal to a sum of the leading chord length and the trailing chord length. a rotor assembly disposed within a stator assembly; the rotor assembly being configured for rotating about a central axis relatively to the stator assembly; the rotor assembly defining a plurality of magnet pockets within the rotor assembly along a radially outboard surface of the rotor assembly, each magnet pocket being substantially rectangular in cross-sectional shape, and each magnet pocket being configured to facilitate insertion of a group of permanent magnet segments into and retention of the group of permanent magnet segments within, the magnet pocket; the rotor assembly further comprising a group of permanent magnet segments disposed in each magnet pocket, the stator assembly comprising a plurality of winding posts, each having a stator tooth at a radially inward end of each of the plurality of winding posts, and each stator tooth defining an inner surface, characterized in that each inner surface consists of a leading planar stator tooth surface, an intermediate planar stator tooth surface, and a trailing planar stator tooth surface, wherein the leading planar stator tooth surface and the trailing planar stator tooth surface are angled toward the central axis with respect to the intermediate planar stator tooth surface, and wherein a leading chord length of the leading planar stator tooth surface is substantially equal to a trailing chord length of the trailing planar stator tooth surface, and an intermediate chord length of the intermediate planar stator tooth surface is equal to a sum of the leading chord length and the trailing chord length.