Explain the concept of controlling fore in connection with a centrifugal governor and state its importance in determining the stability of a centrifugal type governor.
In a spring loaded governor of Hartnell type, the mass of each ball is 1 kg. The length of the vertical arm of the bell crank lever is 100 mm and that of horizontal arm is 50 mm. The distance of the fulcrum of each bell crank lever is 80 mm from the axis of rotation of the governor. The extreme radii of rotation of the balls are 75 mm and 112.5 mm. The maximum equilibrium speed is 5 per cent greater than the minimum which is 360 rpm. Find initial compression of the spring and mass of the sleeve neglecting obliquity of the arms. Also find the equilibrium speed corresponding to the radius of rotation equal to 100 mm.