Sensitiveness: It may be defined as movement of sleeve per unit variation in speed.

Sensitiveness can be measured as N/(N2 – N1)

Where N2 is higher speed, N1 lower speed and N is mean speed at the same radii.

For the same size :

proell governors follow N α (Mg +/- f)/mg

whereas porter governors follow N α M/m

where M is mass of sleeve, m is mass of balls and f is frictional force.

It is clear that sensitiveness of porter governor is independent of friction. Whereas, the value of N will increase in proell governor when f is positive.

Hence, its sensitiveness will be more than that of porter governor.