A rotor assembly for a permanent magnet electric motor defines an axis of rotation and includes a jacket member and a magnet member. The magnet member is received within the jacket member. The magnet member defines a central aperture with a first end and a second end. The axis of rotation extends through the first end and the second end. The rotor assembly further includes a shaft arrangement with a first shaft structure and a second shaft structure. The first shaft structure is received in the first end of the magnet member, and the second shaft structure is received in the second end of the magnet member. The first shaft structure and the second shaft structure are attached within the magnet member at an internal coupling. The shaft arrangement and the jacket member cooperate to compress the magnet member radially with respect to the axis of rotation.