A rotor assembly of an electric motor generally comprises a center shaft configured to rotate about a longitudinal axis and a plurality of spacers extending radially outward from the center shaft, the spacers fixedly attached to the center shaft. A plurality of axially stacked annular laminations are coaxially aligned with the center shaft and radially supported on an inner circumferential surface by the plurality of spacers. Each of the plurality of spacers has, at each axial end of the stacked annular laminations, first and second axial restraining elements extending in an outward radial direction beyond the inner circumferential surface of the plurality of stacked annular laminations. The plurality of stacked annular laminations are compressed between the first axial restraining element and the second axial restraining element, such that an axial compression force is applied to the plurality of stacked laminations.