If the load on an actuator is increased, the flow through a non-compensated flow control valve controlling the actuator speed will _____.

• A. Decrease
• B. Increase
• C. Remain the same
• D. Triple

Answer: (A)

The flow through a non-compensated flow control valve is set by the fixed opening and the pressure drop across it. When the load on the actuator increases, the actuator needs more force and the pressure on the actuator side rises. This reduces the pressure difference across the flow control valve. Since the valve isn’t compensating for changes in pressure, the available flow drops, so less oil reaches the actuator per unit time and the actuator slows down. If the valve were compensated, it could maintain a more constant flow despite changing load, but with a non-compensated valve the flow (and thus speed) decreases as load goes up.