What type of valve is a spool valve mounted in a rotating tube?

What type of valve is a spool valve mounted in a rotating tube?

• A. Modulator
• B. Throttle
• C. Governor
• D. Shift modulator

Answer: (C)

This item tests how a governor uses a hydraulic spool valve housed in a rotating tube to regulate speed. In a centrifugal governor, spinning weights create a centrifugal force that acts on a spool inside a rotating tube. As speed changes, the weights push the spool to move, opening or closing passages that control hydraulic pressure sent to the throttle or fuel metering mechanism. The balance between centrifugal force, spring tension, and hydraulic pressure sets the throttle position to keep engine or system speed at the desired value. When speed rises, the spool movement reduces fuel flow; when speed drops, it allows more fuel flow, stabilizing the RPM. The other options don’t describe this arrangement. A modulator and a shift modulator are terms tied to automatic transmission control rather than a spinning-tube spool valve used for speed regulation. A throttle is the component that actually restricts flow, not the device that modulates it via a rotating-tube spool in a governor.

This item tests how a governor uses a hydraulic spool valve housed in a rotating tube to regulate speed. In a centrifugal governor, spinning weights create a centrifugal force that acts on a spool inside a rotating tube. As speed changes, the weights push the spool to move, opening or closing passages that control hydraulic pressure sent to the throttle or fuel metering mechanism. The balance between centrifugal force, spring tension, and hydraulic pressure sets the throttle position to keep engine or system speed at the desired value. When speed rises, the spool movement reduces fuel flow; when speed drops, it allows more fuel flow, stabilizing the RPM.

The other options don’t describe this arrangement. A modulator and a shift modulator are terms tied to automatic transmission control rather than a spinning-tube spool valve used for speed regulation. A throttle is the component that actually restricts flow, not the device that modulates it via a rotating-tube spool in a governor.