What is the meaning of asynchronous motor

Asynchronism means that the speed of the rotor of three-phase asynchronous motor is lower than that of the rotating magnetic field, that is, it is not synchronous.

Induction motor, also known as induction motor, is a kind of AC motor which produces electromagnetic torque by the interaction of air gap rotating magnetic field and rotor winding induced current, so as to realize the conversion of electromechanical energy into mechanical energy.

Principle of asynchronous motor

According to the rotor structure, asynchronous motor can be divided into two forms: Squirrel Cage (squirrel cage asynchronous motor) and wound rotor asynchronous motor.

An asynchronous motor that operates as a motor. Because its rotor winding current is induced, it is also called induction motor. Asynchronous motor is one of the most widely used and needed motors. About 90% of the machines powered by electricity in various countries are asynchronous motors, of which small asynchronous motors account for more than 70%. In the total load of power system, the power consumption of asynchronous motor accounts for a large proportion. In China, the power consumption of asynchronous motor accounts for more than 60% of the total load.

Asynchronous motor is a kind of AC motor, the ratio of its load speed to the frequency of the power grid is not constant. Induction motor is a kind of asynchronous motor with only one winding connected to the power supply. Under the condition of not causing misunderstanding and confusion, induction motor is generally called asynchronous motor. IEC standard points out that the term “induction motor” is actually used as a synonym of “asynchronous motor” in many countries, while other countries only use the term “asynchronous motor” to express these two concepts.

When the symmetrical voltage is applied to the stator winding of three-phase asynchronous motor, a rotating air gap magnetic field is generated, and the rotor winding conductor cuts the magnetic field to generate the induced potential. Since the rotor winding is in the short circuit state, a rotor current will be generated. The interaction between rotor current and air gap magnetic field produces electromagnetic torque, which drives the rotor to rotate. The speed of the motor must be lower than the synchronous speed of the magnetic field, because only in this way can the rotor conductor induce the electromotive force and generate the rotor current and electromagnetic torque. So the motor is called asynchronous machine, also called induction motor.

Speed of asynchronous motor

The above is the synchronous speed of asynchronous motor, the rated speed is slightly lower than the synchronous speed:

Two pole motor 3000 rpm

Four pole motor 1500 rpm

Six pole motor 1000 rpm

Eight pole motor 750 rpm

Ten pole motor 600 rpm

12 pole motor 500 rpm

16 pole motor 375 rpm

20 pole motor 300 rpm

Editor in charge: yyx

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