Governor sensitivity is the ratio of

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UPSSSC JE Mechanical 2015 Official Paper 2

Option 3 : Mean speed range of speed

__Concept:__

Sensitivity of Governor is defined as the reciprocal of Sensitiveness of governor.

\(Sensitivity~=~\frac{1}{Sensitiveness}\)

\(Sensitivity~=~\frac{mean ~speed}{range~ of~ speed}~=~\frac{N_m}{N_2-N_1}\)

__Additional Information__

- Consider two governors A and B running at the same speed
- When this speed increases or decreases by a certain amount, the lift of the sleeve of governor A is greater than the lift of the sleeve of governor B
- It is then said that the governor A is more sensitive than the governor B
- In general, the greater the lift of the sleeve corresponding to a given fractional change in speed, the greater is the sensitiveness of the governor
- The sensitiveness is defined as the ratio of the difference between the maximum and minimum equilibrium speeds to the mean equilibrium speed

\({\rm{Sensitiveness = }}\frac{{{\rm{Range}}\,{\rm{of}}\,{\rm{Speed}}}}{{{\rm{Mean}}\,{\rm{Speed}}}} = \frac{{{\omega _{\max }} - {\omega _{\min }}}}{{{\omega _{{\mathop{\rm m}\nolimits} ean}}}}\)

- A governor is said to be isochronous when the equilibrium speed is constant (i.e. the range of speed is zero) for all radii of rotation of the balls within the working range, neglecting friction.

__Mistake Points__

- Sensitivity and sensitiveness are two different property of governor which is inversely related.
- Sensitiveness is the Range of speed/Mean speed whereas Sensitivity is Mean speed/Range speed.
- Thus when an isochronous condition happens that N1 = N2 and range becomes zero, it means infinite sensitivity.