Understand the differences between the four major motors in one article
Electric motors are the core power components of modern industrial, household equipment, and automation systems. Different motors are widely used in different fields due to differences in their working principles, performance characteristics, and application scenarios. The following summarizes the differences between AC motors, DC motors, stepper motors, and servo motors from three dimensions: working principles, core characteristics, and application scenarios.

1、 AC Motor

Working principle

Driven by AC power (single-phase or three-phase), the rotating magnetic field generated by alternating current drives the rotor to rotate.

Common types: asynchronous motor (induction motor), synchronous motor.

Core Features

Simple structure: brushless and commutator, low maintenance cost.

Complex speed regulation: Traditional AC motor speed regulation requires a frequency converter, which has a slow response speed.

High reliability: suitable for high-power, long-term continuous operation scenarios.

Application scenarios

Industrial equipment (such as water pumps, fans, compressors), household appliances (such as air conditioners, washing machines).

2、 DC Motor

Working principle

Driven by a DC power supply, the current direction is switched using brushes and commutators to maintain continuous rotation of the rotor.

Common types: brushed DC motor, brushless DC motor (BLDC).

Core Features

Convenient speed regulation: Linear speed regulation can be achieved by changing the voltage or current.

High starting torque: suitable for scenarios that require rapid start-up or load changes.

Brush wear: Brushed motors require regular maintenance, while brushless motors have a longer lifespan but higher cost.

Application scenarios

Electric vehicles, toys, drones, portable devices (such as power tools).

3、 Stepper Motor

Working principle

By controlling the pulse signal, the electrical pulse is converted into a fixed angle step motion (such as rotating 1.8 ° per pulse).

Drive mode: open-loop control, no position feedback.

Core Features

Accurate positioning: suitable for low-speed, high-precision position control scenarios.

Simple control: No need for encoder feedback, low cost.

Easy to lose steps: It may lose steps at high speeds or overload, and reasonable selection is necessary.

Application scenarios

3D printers, CNC machine tools, medical equipment (such as microinjection pumps).

4、 Servo Motor

Working principle

A closed-loop control system provides real-time feedback on position/velocity through an encoder, and the controller adjusts the output to achieve precise control.

Core Features

High precision and high response: Strong dynamic performance, suitable for high-speed and high-precision scenarios.

Complex control: requires drivers, encoders, and control algorithms, resulting in high costs.

No step loss issue: Closed loop feedback ensures accurate actions.

Application scenarios

Industrial robots, CNC machining centers, automated production lines, unmanned aerial vehicle gimbals.

How to choose a motor?
Pursuing low cost and high reliability: Choose AC motors.

Need for simple speed regulation and high torque: choose a DC motor.

Precise positioning, limited budget: Choose stepper motor.

High speed, high precision, dynamic response: choose servo motor.

Summary: Each of the four motors has its own advantages and disadvantages, and the actual selection needs to be comprehensively considered based on power requirements, control accuracy, cost budget, and application scenarios.