Abstract: A method of balancing an embedded permanent magnet motor rotor includes the steps of: a) providing a non-magnetic cylindrical shaft having an axis of rotation and a generally cylindrical surface with an even number of recessed slots defining an even number of ribs therebetween; b) machining an axial slot having a cross-section with a top opening, a bottom and two sides in a center portion of each of the recessed slots; c) sliding at least one balance weight into at least one of the axial slots; and d) inserting locating rods into the axial slot on each side of the at least one balance weight.

Abstract: A method of balancing an embedded permanent magnet motor rotor includes the steps of: a) providing a non-magnetic cylindrical shaft having an axis of rotation and a generally cylindrical surface with an even number of recessed slots defining an even number of ribs therebetween; b) machining an axial slot having a cross-section with a top opening, a bottom and two sides in a center portion of each of the recessed slots; c) sliding at least one balance weight into at least one of the axial slots; and d) inserting locating rods into the axial slot on each side of the at least one balance weight.

Abstract: An insert comprising a lightweight structure configured for filling the gaps between axially spaced C-shaped lamination stacks and circumferentially spaced non-magnetic cradles on a permanent magnet rotor. The insert is secured to a rib by a dovetail tongue that fits within a dovetail groove provided along the length of each rib. The insert engages the adjacent cradles and has a circumferential surface that has the same radius of curvature as the top surface of the cradles.

Abstract: A magnet cradle for supporting a permanent magnet in an overhung recessed slot on the surface of a permanent magnet rotor having an axis of rotation. The cradle is non-magnetic and comprises a top and bottom wall abutting the permanent magnet. The cradle is sized to hold the permanent magnet within the overhung slots. Axial end walls generally perpendicular to the axis of rotation have circumferential edges configured to directly abut overhung portions of the slots. The total axial length of the top and bottom walls of the cradles in the axial direction are greater that the total axial length of the magnet, thereby permitting a magnet to fit between the axial end walls of the cradle without the cradle in the magnetic flux path of the magnet.