An electric motor has a stator and a rotor magnetically coupled to the stator. The rotor has a shaft, a rotor core fixed to the shaft and having a plurality of teeth, a commutator fixed to the shaft adjacent the rotor core and having a plurality of segments, and rotor winding units wound about the teeth and connected to the segments. Brushes arranged in sliding electrical contact with the commutator transfer power to the rotor. Each of the rotor winding units has at least two subcoils directly connected in series to each other and separated from each other by at least one tooth. An initial subcoil and a final subcoil of each rotor winding unit are respectively directly connected to two adjacent segments.