If the speed of the governor fluctuates continuously above and below the mean speed, which of the following statements is true?

Explanation:

Governor:

It is a device used for maintaining a constant mean speed of rotation of the crankshaft over long periods during which the load of the engine may vary.

Governor maintains constant speed by controlling the supply of working fluid as the load varies.

Some important terminologies of the governor.

Sensitiveness:

A governor is said to be sensitive when it readily responds to a small change of speed.

\(Sensitiveness = \frac{{Range\;of\;Speed}}{{Mean\;Speed}} = \frac{{{N_2} - {N_1}}}{N} = \frac{{2\left( {{N_2} - {N_1}} \right)}}{{\left( {{N_1} + {N_2}} \right)}}\)

where N = Mean Speed

N­₁ = Minimum speed corresponding to full load condition.

N₂ = Maximum Speed corresponding to the no-load condition.

Hunting: The sensitiveness of a governor is desired quantity however if a governor is too sensitive, It fluctuates continuously, and this fluctuation is known as hunting.

Isochronism: A governor having infinite sensitivity is treated as an isochronous governor. For all positions of sleeves isochronous has the same speed.

Stability: A stable governor brings the speed of the engine to the required value and there is not much hunting. The ball masses occupy the definite position for the speed of the engine within the working range.

Additional Information 

Controlling force curve for spring-loaded governor

The controlling force is equal and opposite to the centrifugal force and acts radially inward.

Confusion Points

Students often confuse about the work of a governor and flywheel.

Governor: Maintains the constant mean speed of the shaft.

Flywheel: It doesn't maintain a constant speed. It simply reduces the fluctuation of speed.