Three-phase asynchronous motors can be divided into two types: cage type and wound rotor. Asynchronous motors, like other motors, are divided into two parts: the stator and the rotor. The stator construction of cage and wound rotor asynchronous motors is the same, only the structure of the rotor windings is different.

The stator is mainly composed of three parts: stator core, stator winding and frame.
1. Stator core
The stator core is generally made of silicon steel sheets with a thickness of 0.35-0.5mm and coated with insulating paint on the surface. It is part of the magnetic circuit. The shape of the silicon steel sheet is shown in Figure 5-3b. It is a circular ring with several notches of a certain shape punched on the inner circumference. Several pieces are laminated and installed inside the frame. A number of parallel slots are formed on the inner surface of the core. These slots are used to embed the stator windings.

2. Stator winding
Three-phase asynchronous motors have three independent windings, collectively called three-phase windings. Each phase winding is made of several coils according to certain rules. The coils are made of insulated copper wires or aluminum wires, and all coils are regularly embedded into the slots of the stator core. When three-phase alternating current is supplied to the three-phase winding, the three-phase winding can generate a rotating magnetic field. The three first ends and three ends of the three-phase winding are all led to the junction box on the machine base, so that the windings can be connected in a star or delta shape as needed.
3. Machine base
The base may be made of cast iron or welded steel plates. Small-capacity motors are sometimes made of aluminum alloy. The enclosed motor also has heat sinks cast on the outside of the casing.

Stator function of three-phase asynchronous motor
(1) Stator core: Its function is to place the stator winding and form the main magnetic circuit. It is made of 0.5mm thick insulated silicon steel sheets laminated into a cylindrical shape, which reduces the core eddy current caused by the passage of alternating magnetic flux. loss. There are evenly distributed notches in the inner circle of the iron core, which are used to embed the stator winding.
(2) Stator winding: It is the circuit of the stator part. It is made of many high-strength enameled copper wires or aluminum wires connected and wound according to certain rules.
(3) Machine base: fixes and supports the stator core. It is used to install the stator core and fixed end cover, and supports the rotor through the two end covers. Fix the entire motor with sufficient strength.