Question

A governor is said to be stable, if the radius of rotation of balls

• A. increases as the equilibrium speed decreases
• B. decreases as the equilibrium speed decreases
• C. increases as the equilibrium speed increases
• D. decreases as the equilibrium speed increases

Hint:

For a centrifugal governor to operate stably: - High Speed $\rightarrow$ Large Radius $\rightarrow$ Lifts Sleeve $\rightarrow$ Throttles Fuel Down. - Low Speed $\rightarrow$ Small Radius $\rightarrow$ Lowers Sleeve $\rightarrow$ Opens Fuel Up. If the radius decreased as speed increased, it would open the fuel valve further, causing the engine to accelerate uncontrollably!

Answer 1

The Correct Option is C

To understand the stability of a governor, let's explore the concept of governor operation and stability in mechanical engineering. A governor regulates the speed of an engine by adjusting the fuel intake based on load conditions.

In a stable governor, an increase in the speed of the engine should cause an increase in the radius of rotation of the governor balls. This phenomenon ensures that at higher speeds the balls move outward, which causes the engine to slow down by reducing the fuel intake. This behavior reduces instability and maintains the engine speed close to the desired value.

Now, let's analyze the options:

• Option 1: Increases as the equilibrium speed decreases - This indicates that as the engine speed decreases, the balls move outward, which is counterintuitive and leads to instability.
• Option 2: Decreases as the equilibrium speed decreases - A decrease in both speed and radius can lead to a lack of sensitivity and control.
• Option 3: Increases as the equilibrium speed increases - This is the correct behavior for a stable governor. As the speed increases, the centrifugal force causes the radius to increase, allowing the engine to control its speed more effectively.
• Option 4: Decreases as the equilibrium speed increases - This would lead to the balls moving inward during increased speed, resulting in instability and fluctuation in engine speed control.

Therefore, the correct answer is: increases as the equilibrium speed increases.