Induction motor

Induction motor is a type of AC motor. Its structure is mainly divided into stator and rotor. The stator part includes the casing, stator core, stator windings, end covers and bearings, and the rotor part includes the rotating shaft, rotor core and rotor conductors. Induction motors use an external power supply and use electromagnetic induction to rotate the motor's rotor. Induction motors are characterized by the use of alternating current, simple and durable structure, and relatively low manufacturing costs. They are currently the most widely used motors. They can be divided into three-phase induction motors and single-phase induction motors according to the use of power sources.

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Three phase induction motor

The stator winding of the three-phase induction motor generates a rotating magnetic field by applying three-phase alternating current and continues to rotate at a synchronous speed. According to the Arago disk principle, the rotor conductor is cut by the rotating magnetic field, and a corresponding potential is generated on the conductor and a current is induced, causing the rotor conductor to generate torque. Three-phase induction motor rotor conductors are mainly divided into squirrel-cage rotors and wound rotors. The squirrel-cage rotor has a simple structure, is strong and durable, easy to maintain and relatively cheap to manufacture. The wound rotor can control the starting current and starting torque. And the speed control is easy, but the structure is complex and the cost is expensive. Three-phase induction motors are suitable for use in large machines and factory equipment.

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Single phase induction motor

The basic principle of a single-phase induction motor is the same as that of a three-phase induction motor. The biggest difference between the two is that the three sets of windings of a three-phase induction motor generate a rotating magnetic field that remains constant in size but changes in position with time, while a single-phase winding with a single-phase After the power is turned on, it can only produce a pulsating magnetic field whose position changes alternately and whose size changes with time. A single-phase induction motor with only one winding cannot start by itself. Single-phase induction motors are mainly divided into split-phase motors, capacitor motors and shaded pole motors. Compared with three-phase motors of the same horsepower, single-phase motors are larger and less efficient. However, the advantage is that they can be used with ordinary household appliances without the need for an additional three-phase power supply, which is more convenient.