The working principle of asynchronous motors

Place a freely rotating squirrel cage like short-circuit winding in a rotatable horseshoe magnet. When the horseshoe magnet is rotated, the squirrel cage will follow it in the same direction. This is because after the magnet rotates, its magnetic line of force cuts the conductor of the squirrel cage, generating an induced electromotive force in the conductor. According to the right-hand rule, the direction of the electromotive force can be determined. The direction of the electromotive force in the lower half of the conductor faces outward. Due to the short circuit of the squirrel cage conductor, there is current flowing through the conductor under the action of the electromotive force, and the direction of the current is the same as that of the electromotive force. The current in a charged conductor is subjected to force in a magnetic field, and the upper and lower halves of a squirrel cage motor are subjected to force in opposite directions and of equal magnitude, thus forming a torque. This torque will cause the squirrel cage to rotate in the direction of the magnetic field, which is the simple operating principle of an asynchronous motor.