Which motor type is closed-loop with built-in feedback for precise position control?

• A. DC motors
• B. Stepper motors
• C. Servo motors
• D. Induction motors

Answer: (C)

Closed-loop position control relies on feedback to continuously compare the commanded position with the actual position and make corrections. A servo motor is designed as a complete package that includes the motor, a high-resolution sensor (encoder or resolver), and a drive that implements the control loop. This built-in feedback lets the system constantly monitor position and adjust torque or speed to reach and hold the target with high precision, fast response, and repeatability.

Stepper motors can be precise but are typically run in open-loop unless you add external feedback; they don’t inherently carry a built-in closed-loop control in the same way. DC motors can be used in closed-loop systems if an encoder is added, but the standard unit that guarantees integrated closed-loop positioning is the servo motor. Induction motors are robust for constant-speed operation and generally require additional sensing and control hardware to achieve precise position control, rather than having it built-in.