Patent ID: 7345437

Claim:
An electric motor comprising: a rotor having a single armature coil and at least one pair of electrical contacts, wherein each pair of electrical contacts defines the ends of a single continuous circuit of the rotor armature coil; a stator having a first and a second field coil, wherein the first field coil includes a first end and second end, the second field coil includes a first end and second end, and the first and second field coils are positioned on opposite sides of the stator; a first brush and a second brush positioned on opposite sides of the stator wherein the first and second brushes make electrical connections to the electrical contacts on the rotor as the rotor rotates with respect to the stator; and a switch arranged to connect a parallel field coil circuit to a source of DC power and arranged to connect a series field coil circuit to a source of AC power; wherein the series field coil circuit comprises the first end of the first field coil connected to the first brush, the first end of the second field coil connected to the second brush, the second end of the first field coil connected to a first terminal of the switch and the second end of the second field coil connected to a second terminal of the switch; and the parallel field coil circuit comprises the first end of the first field coil connected to a first end of the second field coil, a second end of the first field coil connected to a second end of the second field coil and the second motor brush, and a third terminal of the switch connected to the first end of the first field coil and a fourth terminal of the switch connected to the first brush.