AC motor and DC motor of the main difference

1, talk about the main difference between AC and DC motor:

Brushless DC motor, the stator is a rotating magnetic field, dragging the rotor magnetic field rotation;

AC synchronous motor, but also stator rotation magnetic field dragged rotor magnetic field rotation;

So from the principle, brushless DC motor, AC synchronous motor What is the difference? In the case of

The difference is that the rotation of the magnetic field is different for different reasons:

(1) AC synchronous motor, the stator magnetic field rotation is 120 degrees behind each other three-phase symmetrical AC, stator magnetic field rotation is the change of AC speed;

(2) DC motor, DC power supply is a constant constant voltage, and the actual connection of the coil connected to the formation of the change, and the actual connection with the coil to change the location of the rotor rotation speed;

In this way, their speed control method is different:

(1) AC synchronous motor, the stator magnetic field rotation is 120 degrees behind the three-phase symmetrical alternating current, stator magnetic field rotation is the exchange of changes in speed; as long as the change in AC change speed, you can change the motor speed, speed;

(2) DC motor, DC power supply constant constant voltage, and the actual connection of the coil connected to the formation of the change, and the actual connection with the coil changes only with the speed of rotation of the rotor; as long as the speed of the rotor can change the speed , While the rotor speed and voltage is proportional to change the voltage can change the speed, that is, voltage regulation;

Therefore, the DC motor, asynchronous motor speed method is different, is the structural problem, is the rotation principle of the problem;

* 2, DC motor and asynchronous motor is the fundamental difference between the DC power supply and the coil position depends on the rotor rotation changes, only with the rotor rotation related to the signal to change the DC power supply and the coil position relationship is to achieve speed control of the core issues;

Some people will say that the exchange speed is speed, DC speed is speed, who are the same speed. In the case of

Answer: not the same, DC speed does not change the nature of the motor load, and the exchange speed to change the nature of the load; that is, the frequency is different, the AC motor resistance to different sizes. When the voltage is different, the resistance of DC motor does not change;

Some people will say that what is the relationship? In the case of

The relationship between the great, AC speed, frequency, load nature changes, is a very unstable system. DC speed, load nature of the same, is a very stable system;

Some people will say that what is the relationship? In the case of

Relationship is very large, exchange speed, due to instability, it is difficult to achieve fine speed. The relationship is very large, DC speed, due to stability, it is easy to achieve fine speed, a few millivolts of voltage speed can be resolved. In the case of

3, all the motor, torque is the rotor magnetic field and the stator magnetic field interaction generated;

Different motor, magnetic field movement in different ways, the rotor speed and magnetic field velocity is different. In the case of

(1) AC asynchronous motor, stator rotation magnetic field and rotor rotation magnetic field synchronous interaction to produce torque, rotor speed and magnetic field asynchronous;

(2) synchronous AC motor, the stator rotating magnetic field and the rotor rotating magnetic field synchronous interaction to produce torque, rotor speed and magnetic field synchronization;

(3) rotating armature DC motor, stator magnetic field and rotor magnetic field interaction to produce torque, magnetic field does not move, rotor armature rotation;

(4) Brushless DC motor, the stator rotating magnetic field interacts with the rotor rotating magnetic field to produce torque, rotor speed and magnetic field synchronization;

4, asked: we exchange the synchronous motor rotor stator as the stator, the stator three-phase winding for the rotor, three-phase AC through the slip ring into the three-phase winding, the AC synchronous motor rotor armature rotation, stator magnetic field and rotor magnetic field The synchronous interaction produces the torque, the rotor magnetic field and the stator magnetic field do not move;

I would like to ask, this synchronous AC motor, but also "is the stator magnetic field and the rotor magnetic field interaction generated, but the two magnetic fields are not moving. Rotation is the armature, the armature of the magnetic field does not rotate," how it is not DC motor! You say "DC motor and AC motor essential difference" is "two magnetic fields are not moving.