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Why is it called asynchronous motor?
- Dec 06, 2018 -

Analysis of working principle of asynchronous motor

Why is it called asynchronous motor?

A three-phase asynchronous motor that operates as a motor. The rotation speed of the rotor of the three-phase asynchronous motor is lower than the rotation speed of the rotating magnetic field, and the rotor winding induces electromotive force and current due to the relative motion between the rotor and the magnetic field, and interacts with the magnetic field to generate electromagnetic torque to realize energy conversion.

The meaning of "asynchronous" of a three-phase asynchronous motor is that the rotor speed is always lower than the synchronous speed during the electric operating state. The stator winding is connected to a three-phase alternating current to generate three magnetic fields, and a rotating magnetic field is synthesized in the stator air gap. The rotational speed of this rotating magnetic field is called the synchronous rotational speed. The stationary rotor windings are magnetically moved relative to the magnetic field to induce an electromotive force.

The rotor winding is closed and a rotor current is generated. This current interacts with the rotating magnetic field to generate an electromagnetic torque in the rotor winding that drives the rotor to rotate in the direction of the rotating magnetic field. However, the speed of the rotor is never synchronized with the speed of the rotating magnetic field. Especially if it is synchronized, the rotor winding and the magnetic field have no relative motion and cut the magnetic lines of force, and no induced electromotive force and induced current are generated. The rotor cannot continue to rotate. Therefore, the rotor speed is always slightly lower than the synchronous speed.

An asynchronous motor is an AC motor based on an air gap rotating magnetic field that interacts with an induced current in a rotor winding to generate electromagnetic torque for energy conversion. Since the rotor winding current is induced, there is a difference between its speed and the synchronous speed.

The difference between asynchronous motors and other motors has the following characteristics:

1, simple structure, easy to maintain

2, the power is taken from the power grid, easy to use

1, poor speed performance

2, the efficiency is lower than DC motor