Question

A Servo Motor differs from a standard motor because it:

• A. Cannot be used for AC
• B. Operates only at very high speeds
• C. Features a feedback mechanism for precise control
• D. Does not have a rotor

Hint:

A servo motor is defined by its closed-loop control capability, not by whether it runs on AC or DC.
The encoder/sensor on the back of the motor shaft is the telltale sign of a servo system.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
This question asks to identify the key characteristic that distinguishes a servo motor from standard industrial motors (such as general induction motors or DC motors).

Step 2: Key Formula or Approach:
The difference lies in the control scheme.
Standard motors typically run in an open-loop system, whereas servo motors operate in a closed-loop control system.

Step 3: Detailed Explanation:

• Standard motors are designed for continuous power delivery and speed control, usually operating in an open-loop fashion without automatic position correction.

• A servo motor is part of a closed-loop feedback control system designed for precise control of angular or linear position, velocity, and acceleration.

• A servo motor consists of three main elements: a motor (AC or DC), a feedback sensor (such as an encoder, resolver, or potentiometer), and a controller.

• The sensor continuously monitors the actual position or speed of the motor shaft and sends this feedback signal to the controller.

• The controller compares the feedback signal with the desired target command.

• If any error exists, the controller applies a correction signal to the motor driver to eliminate the discrepancy.

• This feedback loop allows servo motors to achieve high accuracy and fast dynamic response, making them suitable for robotics, CNC machines, and automated manufacturing.

Step 4: Final Answer
Therefore, a servo motor differs from a standard motor because it features a feedback mechanism for precise control, which matches option (C).