The working principle of three-phase asynchronous motor

- Nov 29, 2018-

When a symmetrical three-phase alternating current is supplied to the three-phase stator winding, a rotating magnetic field is generated which rotates clockwise in the stator and rotor inner circular spaces at the synchronous rotational speed n1. Since the rotating magnetic field rotates at the n1 rotational speed and the rotor conductor is initially stationary, the rotor conductor will cut the stator rotating magnetic field to generate an induced electromotive force (the direction of the induced electromotive force is determined by the right-hand rule). Since both ends of the rotor conductor are short-circuited by the short-circuiting ring, an induced current which substantially coincides with the direction of the induced electromotive force is generated in the rotor conductor under the action of the induced electromotive force. The current-carrying conductor of the rotor is subjected to an electromagnetic force in the stator magnetic field (the direction of the force is determined by the left-hand rule). The electromagnetic force generates an electromagnetic torque to the rotor shaft, and drives the rotor to rotate in the direction of the rotating magnetic field.

Through the above analysis, it can be concluded that the working principle of the motor is: when the three-phase stator windings of the motor (each phase difference of 120 degrees), after entering the three-phase symmetrical alternating current, a rotating magnetic field will be generated, which rotates the rotor winding, thereby Inductive current is generated in the rotor winding (the rotor winding is a closed path), and the current-carrying rotor conductor generates electromagnetic force under the rotating magnetic field of the stator, thereby forming electromagnetic torque on the motor shaft, driving the motor to rotate, and rotating and rotating the motor The direction of the magnetic field is the same.