A motor that converts AC electrical energy into mechanical energy is called an AC motor. It consists of a rotating rotor and a stationary stator. Usually, the rotor consists of a rotor core and rotor windings, and the stator consists of a stator core and stator windings. The interaction of magnetic fields, consisting mainly of the induction motor and rotating magnetic field principles, is the basis for the operation of AC motors. The current fed into the stator coil by the AC power supply produces a rotating magnetic field, which is similar to magnetic lines of force and forms a toroidal magnetic field in space.
According to the principle of an induction motor, the rotor is subjected to an induced electromotive force from the rotating magnetic field, which causes the rotor to generate a current. Due to the interaction of current and magnetic field, the rotor will rotate and feel the torque. The speed of an AC motor can be varied over a wide range in a number of ways to meet a variety of needs and operating situations. AC motors have the advantages of simple design, reliable performance, wide speed range, low starting current, and a wide range of applications. However, AC motors have some drawbacks, including expensive production costs, difficulty in speed control, poor efficiency, limited starting torque, and harmonic pollution of the grid.
According to the different ways of classification, AC motors can be categorized in the following ways:
Three-phase asynchronous motors can be divided into squirrel-cage and wire-wound according to their rotor structure, of which the squirrel-cage type is the most widely used.
AC motors are widely used in many fields. AC motors are often used in industry to drive a variety of machinery and equipment, including pumps, fans, compressors, rolling mills, cranes, and other heavy equipment. In order to power this equipment, the power supply to the motor must be reliable, efficient, and adjustable. AC motors fulfill these needs. Apart from industrial production, AC motors are also used in a wide range of equipment in the commercial sector, including electric fans, washing machines, air conditioners, elevators, and refrigerators. This is due to the fact that AC motors are able to provide stable speed and efficient energy conversion, and most of these applications require motors that are safe, reliable, energy efficient, and low-noise.