The stator of asynchronous motor consists of stator core, stator winding and frame.
1. Stator core
The stator core is used as a part of the magnetic circuit of the motor and embedded in the stator winding. The stator core is formed by laminating silicon steel sheets with a thickness of 0.5 mm, and both sides of the brick-shaped steel sheets are coated with insulating paint to insulate the steel sheets from each other, so as to reduce the core loss caused by the rotating magnetic field in the stator core. The inner circle of the stator core is stamped with several identical slots for embedding the stator winding.
2. Stator winding
Stator winding is the circuit part of the motor, and its main function is to generate induced potential through current and realize the conversion of electromechanical energy. The distribution of winding coils in stator slots can be divided into single layer and double layer. In order to obtain better electromagnetic performance, medium and large ABB asynchronous motors adopt double-layer short-distance windings.
3. Stator frame
The main function of the frame is to fix and support the stator core, so it is required to have sufficient mechanical strength and rigidity to withstand various forces during motor operation or transportation. Small and medium-sized AC motors-generally use cast iron base, for large-capacity AC motors, generally use steel plate welder base.
The rotor of asynchronous motor consists of rotor core, rotor winding and rotating shaft.
1. Rotor core
Rotor core is a part of motor magnetic circuit. Together with the stator core and air gap, it forms the whole magnetic circuit of the motor. Generally, 0.5mm thick silicon steel sheets are stacked in the rotor core. Most of the rotor cores of small and medium-sized AC motors are directly mounted on the motor shaft. The rotor core of a large AC motor is installed on a rotating bracket which is sleeved on the rotating shaft.
2. The role of rotor winding is to induce potential, flow current and generate electromagnetic torque, and its structural forms are squirrel-cage type and winding type.
1. squirrel cage rotor
Squirrel cage rotor winding is a self-closing winding. A guide rod is inserted into each rotor slot, and two end rings are respectively connected with the two ends of all the guide rods at the notches extending out of the two ends of the iron core. A6 If the iron core is removed, the whole winding looks like a "round cage", so it is called a squirrel-cage rotor.
2. Wound rotor
The winding rotor winding is similar to the stator winding, and it is a three-phase symmetrical winding. The insulated conductor is embedded in the rotor core slot and connected in a star shape. Then connect the three ends of the small wire to the three slip rings rotating on the shaft respectively, and then draw out the current through the brush. The characteristic of wound rotor is that external resistance can be connected to winding circuit through slip ring and brush to improve the starting performance of motor or adjust the speed of motor. In order to reduce the wear of brushes, wound asynchronous motors are sometimes equipped with brush-lifting short-circuit devices, so that when the motor is started without speed regulation, the brushes are lifted and three slip rings are short-circuited at the same time.