The capacitor running motor is composed of a stator assembly, a rotor assembly and a support assembly. The stator is connected to the AC power grid, and the rotor generates induced current and electromagnetic torque by electromagnetic induction, so as to achieve the purpose of converting the electromechanical energy. When the current flows into the stator winding, the current generates two current loops in the main winding and the secondary winding of the stator component respectively. Due to the influence of the capacitance of the secondary winding, the current in the secondary winding is about 90 degrees in phase ahead of the current in the main winding, so that a rotating magnetic field will be generated in the air gap and rotate at synchronous speed. When the rotating magnetic field cuts the rotor conductor, an induced potential is generated in it, and the direction of the potential is judged by the right hand rule. Because the rotor winding is short-circuited (cast aluminum rotor), there is current flowing in the rotor conductor, and the current in the rotor conductor acts with the air gap magnetic field to produce electromagnetic torque, and the direction of torque is judged by the left-hand rule. It is in the same direction as the rotating magnetic field, and under the action of electromagnetic torque, the rotor rotates in the direction of the magnetic field at a speed (less than the synchronous speed).