Which type of servo motor is typically used in computer-related devices and CNC machines where starts and stops must occur quickly and accurately?

• A. DC servo motor
• B. AC servo motor
• C. Stepper motor
• D. Brushless DC motor

Answer: (A)

Closed-loop, high-speed position control is what makes a DC servo motor well suited for fast, accurate starts and stops. In a DC servo setup, the motor is paired with an encoder (feedback), so the drive constantly compares actual position to the command. When a quick move is needed, the controller quickly adjusts the armature voltage to produce rapid torque and acceleration. The feedback loop continuously corrects any error, allowing the motor to reach the exact position and stop precisely where intended. This combination of fast dynamic response and precise closed-loop control is why DC servo motors are commonly used in computer-related devices and CNC machines where timing and exact stopping points matter. While other motors can perform similar tasks, they often rely on open-loop control or have different performance tradeoffs, which makes the DC servo approach a common and effective choice for rapid, accurate positioning.