How do Servo Motors Work

The term "servo" is derived from the Latin (Latin "servus" = servant). This means that each motor used for (exact) positioning or to remain constant torque or speed can be named as servo motor.

For this purpose, however, a closed-loop control with appropriate sensors are necessary. The servo motors themselves form part of this closed-loop control.

Thus, there is generally no limitation, which types of electric motors are actually used as servomotors. Thus, a DC motor, a synchronous motor or asynchronous motor, even a stepper motor with rotor position detection can be used as a "servomotor".

How a servo drive works - simplified illustration

How a servo drive works - simplified illustration

If one speaks of servo drive, then usually the combination of servomotor and servo controller is meant, which together form a closed-loop control (position, speed, torque).

Servo drive = Controller + Servomotor

In this video below you get the functioning of a servo motor and how the components of a servo drive system work together. From the content:

  • Introduction Servo motor
  • Clarify the terms Servo motor and Servo Drive systems in general
  • Sensor feedback device as a part of the servo drive
  • The components of a Servo Motion Control System
  • Structure and functioning of a AC servo motor

This can also be of interest for you:

Resolver, Incremental encoder, absolute encoder, position sensor (direct, indirect), Hall sensors