Three phase asynchronous motors play a significant role in engineering applications due to their simple structure and affordable price. Three phase asynchronous motors are induction motors, which correspond to single-phase asynchronous motors. However, single-phase asynchronous motors use a voltage of 220V, while three-phase asynchronous motors use 380V three-phase alternating current, So what is the principle of this three-phase asynchronous motor? Let's take a look at the basic principles of three-phase asynchronous motors together.

What is the principle of three-phase asynchronous motor

This type of motor has a stator whose three-phase winding is completed in a spatial position, and its basic principle is that when we introduce the so-called three-phase symmetrical alternating current into the stator winding, a constant speed rotating magnetic field will be established inside the motor. This magnetic field is the selected magnetic field, which is a comparative condition and basic basis for the operation of this asynchronous motor.

And the generation of this magnetic field is actually the so-called working principle of asynchronous motors. The generation of this rotating magnetic field is actually that each phase has only one coil, and there are three identical coils in the motor, each located in the stator core slot. The wiring method of this three-phase asynchronous motor is a star shaped wiring method. Once the power supply of the machine is powered on, the stator winding will also generate symmetrical currents.

After entering a three-phase symmetrical current in the stator winding, a rotating magnetic field is generated internally. There is an opposing motion between the rotor and the rotating magnetic field, and the magnetic field lines are cut, resulting in a certain induced electromotive force. The formation of this electromotive force is mainly determined by the right-hand rule, and the rotor winding is closed.

So when an induction motor works, there will also be current flowing through the winding,

At this point, there will be an interaction between the rotor and the rotating magnetic field, and electromagnetic force will also be generated in the rotor winding, and the direction of other forces will be determined by the left-hand rule.

The electromagnetic relationship of three-phase asynchronous motors

The relationship between three-phase asynchronous motors and electromagnetism is actually quite similar to the relationship between motors and transformers we see in daily life, because the stator winding of asynchronous motors is actually similar to the winding of transformers every time they are used, and the rotor winding in the motor actually has the same effect as the secondary winding of transformers, but it is not a normal winding process, but a winding that is equivalent to its short-circuit.

Of course, there is still a big gap between the three-phase asynchronous motor and the transformer, as the transformer is concentrated on the iron core, while the three-phase asynchronous motor is indeed distributed inside the machine on the inner wall of the iron core. There is also a relatively large air gap in the magnetic circuit of the three-phase asynchronous motor.

The method for adjusting the electromagnetic capability of an asynchronous motor is to change the speed of the rotor, which can cause a significant change in the electromagnetic torque. Therefore, when the equipment has a load demand, a three-phase asynchronous motor is used to achieve its balance. If the equipment load changes, the motor will also be adjusted appropriately. When the load torque decreases, the motor will accelerate, and vice versa, it will decelerate.