What Is the Difference Between a Rotary Actuator and a Motor

In the world of industrial automation and robotics, both rotary actuators and motors are essential components used to generate rotary motion. While they may appear to perform similar functions, their structure, function, and application reveal key differences. So, what is the difference between a rotary actuator and a motor?

Function and Purpose

A motor is an electromechanical device that converts electrical energy into mechanical rotary motion. It provides continuous or variable-speed rotation and is often used in applications such as fans, pumps, conveyors, and machine tools. Motors—whether AC, DC, or servo—are core driving elements in most mechanical systems.

A rotary actuator, on the other hand, is a device designed to produce limited-angle rotary motion, typically in a controlled and precise manner. It can be powered by electric, pneumatic, or hydraulic energy. Rotary actuators are often used for automated positioning, robotic joints, and valve control, where precise angular displacement is critical.

Range of Motion

Motors generally provide continuous 360-degree rotation, ideal for driving wheels or rotating parts indefinitely.

Rotary actuators typically offer limited-angle rotation—for example, 90°, 180°, or 270°—making them more suited for angular positioning tasks or swing motions.

Control and Integration

Rotary actuators are often integrated systems that combine motion generation with position feedback and control elements. Some include built-in gearboxes, sensors, and limit stops, offering plug-and-play solutions for automation systems.

Motors usually require additional components—such as encoders, controllers, and gearboxes—to achieve the same level of precision and control in complex applications.

Conclusion

While motors are the powerhouses behind general rotary motion, rotary actuators are specialized devices designed for precise, limited-range rotation. Understanding their differences helps engineers and designers choose the right solution for tasks ranging from continuous rotation to highly accurate angular positioning.

In today’s smart manufacturing era, selecting between a motor and a rotary actuator depends on the application’s specific demands for torque, control, range of motion, and integration.