An electrically-assisted turbocharger includes a shaft extending along an axis, a compressor wheel, a turbine wheel, a housing, and an electric machine. The electric machine includes a rotor rotatably coupled to the shaft and a stator lamination stack radially spaced from the rotor. The stator lamination stack has circumferentially spaced teeth defining gaps therebetween. The electric machine also includes a coil winding disposed in the gaps between the circumferentially spaced teeth and a guard plate disposed at one of the first and second stator ends. The guard plate extends radially away from the axis and includes a plurality of teeth guards extending radially, with each of the teeth guards aligned with one of the teeth of the stator lamination stack to electrically insulate the coil winding from the teeth of the stator lamination stack.