There are two types of three-phase asynchronous motors: squirrel cage type and wound type

In order for the asynchronous motor to allow the rotor to rotate freely, a certain air gap is left between the stator and the rotor. In this way, the magnetic circuit of the motor is composed of stator and rotor cores and an air gap, and the air gap is the main part of the reluctance of the magnetic circuit. The smaller the air gap, the smaller the excitation current required to establish a magnetic field of the same size. Therefore, the air gap of the asynchronous motor is very small, such as the air gap of the medium and small motors is generally only about 0.2~1.0mm.

The rotor is the rotating part of the motor, mainly composed of rotor core, rotor winding and rotating shaft.

The rotor core is a part of the magnetic circuit of the motor. The whole core is cylindrical and made of laminated silicon steel sheets with a thickness of 0.5 mm. There are evenly distributed grooves on the outer surface of the outer circle for placing the rotor winding. The rotor core is mounted directly on the shaft. The rotor winding is divided into two types according to its structure: squirrel cage type and wound type.

For squirrel-cage asynchronous motors with a rated power above 100kW, copper bars are embedded in the rotor iron core slot, and the two ends of the copper bars are welded with an end ring to form a closed circuit.

The stator is the fixed part of the motor, mainly composed of stator core, stator winding and machine base.

As a part of the magnetic circuit of the motor, the stator core is generally laminated with 0.5mm thick silicon steel sheets with good magnetic permeability. The surface of the silicon steel sheets is coated with insulating varnish to insulate the sheets from each other. Evenly distributed grooves are punched on the inner circle of the stator core, which are used to embed the stator winding.

The three-phase asynchronous motor is mainly composed of two parts, the stator and the rotor. The stationary part is called the stator, and the rotating part is called the rotor. There is a small gap between the stator and the rotor, called the air gap. There are two types of three-phase asynchronous motors: squirrel cage type and winding type. The basic working principle of the two is the same, and the stator structure is also the same, but the rotor structure is obviously different.