Patent ID: 8237395

Claim:
A dual-speed single-phase AC motor, comprising a stator, comprising a stator core; and a coil winding, comprising a starting winding, a first main winding, and a second main winding; a rotor, and a starting circuit, comprising a rectifying and voltage-stabilizing circuit, a detecting circuit, a voltage comparison circuit, a first switching circuit, a second switching circuit, and a third switching circuit; wherein the number of poles of said starting winding is the same as that of said first main winding; the number of poles of said first main winding is less than that of said second main winding; during low-speed starting, said first switching circuit is serially connected to said first main winding, and then to a utility AC power supply, said second switching circuit is serially connected to said second main winding, and then to said utility AC power supply, said third switching circuit is serially connected to said starting winding, and a starting capacitor, and then to said utility AC power supply, a signal input end of each of said first switching circuit, said second switching circuit, and said third switching circuit is connected to an output end of said voltage comparison circuit, another signal input end thereof is connected to the ground, or to an output end of said rectifying and voltage-stabilizing circuit, and said first switching circuit, said third switching circuit, and said second switching circuit form an interlocking relationship; as said first switching circuit and said third switching circuit are closed, said second switching circuit is opened, said first main winding and said starting winding are energized and operate, and said second main winding stops operating; and as said first switching circuit and said third switching circuit are opened, said second switching circuit is closed, said first main winding and said starting winding are de-energized and stop operating, and said second main winding is energized and operates.