In modern industry, motors are an essential part of our production and life. Induction motor is one of them, which is widely used in various mechanical equipment and electronic products. So, what is an induction motor?

Induction motor is a kind of AC motor, which uses the principle of electromagnetic induction to generate rotational force. It consists of a stationary stator and a rotating rotor. In a miniature motor, there is a rotating magnetic field on the stator that comes from a three-phase power supply. Inside the rotor there is a conductor and when the rotating magnetic field acts on the conductor, it induces an electric potential which produces a current. This current creates a magnetic field inside the rotor that interacts with the magnetic field of the stator, which causes the rotor to start rotating. This is the basic working principle of a miniature induction motor.

There are many different types of miniature motors, and they are categorized primarily based on the rotor structure and principle of operation. The most common are squirrel cage induction motors and bipolar induction motors.

The rotor structure of a squirrel cage induction motor is similar to a mouse cage in that it consists of a number of conductors arranged in parallel. These conductors are connected together to form a circuit, usually made of aluminum or copper. When the rotor begins to rotate, an induced current is generated in these conductors, which produces rotational force. Squirrel cage induction motors are widely used because of their simple construction, ease of manufacture and high reliability.

Bipolar induction motor is a type of motor used for low speed rotation. It is characterized by two magnetic poles of opposite polarity inside the rotor. When the rotating magnetic field of the stator is applied to the rotor, the magnetic poles produce a drifting motion, which causes the rotor to start rotating. Bipolar induction motors are mainly used in applications that require low speed and high torque, such as electric locomotives, due to the complexity and high cost of the rotor structure.

Apart from squirrel cage induction motors and bipolar induction motors, there are many other types of induction motors, such as asynchronous motors, synchronous motors, and electric brakes, all of which have their own characteristics and different application scenarios.

Induction motors have the advantage of being able to automatically adjust the speed and load within a certain range. They have the advantages of high efficiency, low noise, and long life in use, so they are widely used in many fields.

In short, induction motors are highly efficient, reliable and economical electric motors with a wide range of applications. Understanding the basic working principles and different types of induction motors is important for a better understanding of modern industrial and electromechanical equipment.