Subway traction motor adopts three-phase rat cage asynchronous electric motor, using frequency conversion and variable voltage speed regulation mode. The traction converter output three-phase AC power to power the stator winding of the traction motor.The rotating magnetic field is generated on the motor stator winding, which cuts the rotor conductor to sense the electromotive force and current. The rotor conductor is exerted by the electromagnetic force under the action of the magnetic field, forming the electromagnetic torque, driving the motor rotation, converting the electric energy into mechanical energy, and driving the train to run.