An independent speed control circuit may be with a double-acting cylinder because ______.

An independent speed control circuit may be with a double-acting cylinder because ______.

• A. Aiding loads are present
• B. Equal extend and retract speeds are needed
• C. Two speeds are needed during extend
• D. Two different pressures are needed

Answer: (B)

The key idea is that the speed of a double-acting cylinder depends on the flow rate and the piston area on each side. Because the rod takes up area on one side, the extend side and the retract side don’t have the same effective area. If you use a single speed control for both directions, the same flow will move the larger-area (extend) side more slowly and the smaller-area (retract) side more quickly, so the two strokes won’t match in speed. An independent speed control circuit lets you throttle the extend and retract paths separately. By adjusting each path’s flow, you can make the extend and retract speeds equal, even though the piston areas differ. This is why the option stating equal extend and retract speeds are needed is the best fit. The other choices don’t address the need to balance speeds in both directions. Aiding loads, two different pressures, or two speeds during extend alone isn’t what creates the same motion rate on both strokes.

The key idea is that the speed of a double-acting cylinder depends on the flow rate and the piston area on each side. Because the rod takes up area on one side, the extend side and the retract side don’t have the same effective area. If you use a single speed control for both directions, the same flow will move the larger-area (extend) side more slowly and the smaller-area (retract) side more quickly, so the two strokes won’t match in speed.

An independent speed control circuit lets you throttle the extend and retract paths separately. By adjusting each path’s flow, you can make the extend and retract speeds equal, even though the piston areas differ. This is why the option stating equal extend and retract speeds are needed is the best fit.

The other choices don’t address the need to balance speeds in both directions. Aiding loads, two different pressures, or two speeds during extend alone isn’t what creates the same motion rate on both strokes.