An electric motor assembly includes a stator and a rotor configured to rotate relative to the stator. The stator includes a stator core including a yoke that has a ring shape and a plurality of teeth radially coupled to an inner surface of the yoke, a stator coil that is wound around the stator core, and an insulator disposed between the stator core and the stator coil. The insulator includes a yoke insulator that is coupled to the yoke with a first coupling tolerance defined between the yoke insulator and the plurality of tooth insulators, and a plurality of tooth insulators that are coupled to the plurality of teeth, respectively, with a second coupling tolerance defined between the yoke and the plurality of teeth. The first coupling tolerance is less than the second coupling tolerance.