An internal permanent magnet machine comprising: a stator assembly comprising a stator core, the stator core comprising a plurality of stator teeth, the stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity; and a rotor assembly comprising a rotor core , the rotor assembly disposed inside said cavity and configured to rotate about the longitudinal axis, wherein the rotor assembly comprises: a shaft comprising a plurality of protrusions alternately arranged relative to a plurality of bottom structures ; a plurality of stacks of laminations , the stacks disposed on the protrusions and dovetailed circumferentially around the shaft ; a plurality of a pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque; each pair of permanent magnets disposed between the stacks of laminations ; a plurality of middle wedges mounted between each pair of permanent magnets ; and a plurality of top wedges mounted on the plurality of permanent magnets for containing the plurality of permanent magnets ; wherein the plurality of top wedges and the plurality of middle wedges comprise non-metallic wedges. a stator assembly comprising a stator core, the stator core comprising a plurality of stator teeth, the stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity; and a rotor assembly comprising a rotor core , the rotor assembly disposed inside said cavity and configured to rotate about the longitudinal axis, wherein the rotor assembly comprises: a shaft comprising a plurality of protrusions alternately arranged relative to a plurality of bottom structures ; a plurality of stacks of laminations , the stacks disposed on the protrusions and dovetailed circumferentially around the shaft ; a plurality of a pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque; each pair of permanent magnets disposed between the stacks of laminations ; a plurality of middle wedges mounted between each pair of permanent magnets ; and a plurality of top wedges mounted on the plurality of permanent magnets for containing the plurality of permanent magnets ; a shaft comprising a plurality of protrusions alternately arranged relative to a plurality of bottom structures ; a plurality of stacks of laminations , the stacks disposed on the protrusions and dovetailed circumferentially around the shaft ; a plurality of a pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque; each pair of permanent magnets disposed between the stacks of laminations ; a plurality of middle wedges mounted between each pair of permanent magnets ; and a plurality of top wedges mounted on the plurality of permanent magnets for containing the plurality of permanent magnets ; wherein the plurality of top wedges and the plurality of middle wedges comprise non-metallic wedges. <EOS>