The most common motor classification: DC and AC

Last updated: June 1, 2026

The two most common motor categories are DC motors and AC motors: DC motors are further divided into brushed and brushless types, while AC motors are divided into synchronous and asynchronous types, with asynchronous (induction) motors further split into single-phase and three-phase. Different motors have different characteristics and suitable applications. Below we explain the differences, pros and cons, and selection criteria for DC and AC motors.
 

DC Motors

DC motors can be divided into brushed DC motors and brushless DC motors. DC motors have good starting and speed-regulation characteristics, and are common in applications requiring precise control such as power tools, toys, and servo systems. In brushed motors using carbon brushes, the armature wears down with operation, giving a shorter lifespan and requiring periodic brush replacement; brushless DC motors require less maintenance but are usually more costly and have a more limited application range.
 

AC Motors

AC motors can be divided into synchronous motors and asynchronous motors. Compared with asynchronous motors, synchronous motors can deliver the same output in a smaller size, but the permanent magnets they use are limited and rare on Earth, significantly raising manufacturing costs. Asynchronous motors are heavier and larger at the same power and torque, but are more cost-effective and easier to maintain. Asynchronous motors, also called induction motors, can be subdivided into single-phase and three-phase motors, and are common in industrial pumps, fans, compressors, and conveyor belts. Owing to their high reliability and stability, asynchronous motors have become the most widely used motor category across industries and daily life.
 

Difference	DC Motor	AC Motor
Power Source	Requires DC power	Requires AC power
Structure	Simple structure, usually rotor and stator	More complex, usually multiple windings and three-phase power
Brushes	Brushed type uses brushes; brushless type does not	No brushes needed; rotor driven by induced current
Speed	Speed adjusted by varying voltage	Speed usually determined by supply frequency
Control	Direction and speed controlled by changing voltage magnitude and polarity	Requires a more complex electronic controller for direction and speed
Typical Applications	Power tools, toys, servo systems	Industrial pumps, fans, compressors, conveyors

 

How to Choose Between DC and AC Motors

The choice of motor type should be based on the specific application. If high-precision control and accurate speed regulation are needed, a DC motor is usually more suitable; if simple operation and cost-effectiveness are priorities, an AC motor is usually more suitable. You should also consider the required torque, speed range, and load characteristics, then choose the most suitable motor type after an overall evaluation.