The main differences between AC motors and DC motors are as follows:

1. Working principle
DC motors rely on DC power to work, and change the direction of current through commutators or brushes to keep the rotor rotating in one direction. AC motors use AC power, and since the direction of AC current changes periodically, no commutator or brushes are required. In contrast, AC motors use the principle of electromagnetic induction to rotate.

2. Structure
The structure of DC motors is relatively complex, mainly consisting of stators, rotors, commutators and brushes. The structure of AC motors is relatively simple, mainly consisting of stators and rotors, and no brushes or commutators are required.

3. Control method
The speed of DC motors can be controlled by adjusting the power supply voltage and armature current. Since the rotating magnetic field of AC motors is generated by the power supply, the speed needs to be controlled by devices such as electronic inverters.

4. Application areas
DC motors can usually control their speed easily, so they are often used in applications that require precise speed control, such as robots, power tools, etc. AC motors are simple, rugged and require less maintenance. They are often used in fixed speed applications, such as household appliances such as electric fans and air conditioners, as well as pumps, compressors and conveyor belts in industrial production.


5. Speed ​​regulation method
DC motors can achieve speed regulation by changing the armature voltage or magnetic field strength. AC motor speed regulation is usually achieved through a frequency converter, which controls the motor speed by changing the power supply frequency.

6. Summary
The choice of DC motor or AC motor depends on the specific application requirements. DC motors are more advantageous in situations where precise speed control and fast start-up are required, while AC motors are more suitable in situations where simplicity, ruggedness and less maintenance are required.

Source:https://www.planetminecraft.com/blog/how-to-distinguish-dc-motor-and-ac-motor/