Motor driven proportional control valves are generally slower to operate than pneumatic control valves.

• A. Faster
• B. Slower
• C. About the same
• D. Not sure

Answer: (B)

Actuator response speed is driven by the actuation method. Electric motor–driven proportional valves move a relatively heavy spool through gears or a screw, so they suffer from inertia, friction, and possible backlash. The control loop must accelerate and decelerate this moving mass, which slows how quickly the valve can reach a new position. In contrast, pneumatic proportional valves use compressed air to move a diaphragm or light piston, with far less moving mass and very rapid air-pressure changes, allowing quicker initial motion and faster overall response. That combination makes motor-driven proportional valves generally slower to operate than pneumatic ones.