The 5 Types of Servo Motors

What Are Servo Motors? A Brief Introduction

A servo motor is a closed-loop mechanism that controls motion using positional feedback. They can use either an analog or digital signal representing a positional command for the output shaft.

Servo motors are either linear or rotational actuators that control angular or linear position. In more advanced versions, they also control velocity and acceleration. Each servo motor consists of a motor, potentiometer, and a control circuit that receives commands in analog or digital inputs. The controller interprets the signal and tells the servo motor where and how to move.

Different Uses of Servo Motors

Different servo motor applications are available to you depending on the type of mechanism you use. Dozens of industries and engineering firms rely on servo motors for myriad reasons. These mechanisms contribute to improved worker safety, speed, and efficiency through automation and waste reduction by optimizing various processes. The number of uses of servo motors continues to grow year over year, and a few industry examples includes:

1. DC Servo Motor

DC servo motors are the oldest variety of servomechanism. The frequency of the electrical input controls them. These servos are accurate, fast, and highly responsive to start/stop command signals. They are commonly found in CNC machines and other hardware.

2. AC Servo Moto

AC servo motors can be controlled by both voltage and frequency, allowing for multiple control avenues. They have high accuracy and precision in movement speed and position. AC servo motors are versatile and used in robotics, CNC machinery, and other applications requiring precision and variability.

3. Positional Rotation Servo Motor

The positional rotation servo motor's output shaft is capable of 180° of rotation, making it one of the most common types of servomechanism in today's manufacturing environments. Physical stops inside the mechanism protect the sensor by preventing excess turning. These servo motors are used daily in remote-controlled cars, commercial planes, toys, and more.

4. Continuous Rotation Servo Motor

A continuous rotation servo motor is also extremely common. Instead of a 180° rotational arc, this servomechanism can rotate in any direction indefinitely. The control signal measures the speed and direction of rotation. Both the direction of rotation and the speed of the rotation can be controlled via the command signal.

5. Linear Servo Motor

Instead of rotating 180° or 360°, a linear servo motor has an extra set of gears that changes the output shaft's movement from circular to back and forth. This type of servo motor is often used as a guide for CNC machines to move linearly across the surface of a downdraft table.