Question

A governor is said to be stable, if the

(a) radius of rotation of balls increases as the equilibrium speed decreases

(b) radius of rotation of balls decreases as the equilibrium speed decreases

(c) radius of rotation of balls increases as the equilibrium speed increases

(d) radius of rotation of balls decreases as the equilibrium speed increases

This question was addressed to me in an international level competition.

The origin of the question is Porter Governor topic in section Governors of Machine Dynamics

Answer 1

The correct answer is (c) radius of rotation of balls increases as the equilibrium speed increases

Easiest explanation: A governor is said to be stable when for every speed within the working range there is a definite configuration i.e. there is only one radius of rotation of the governor balls at which the governor is in equilibrium. For a stable governor, if the equilibrium speed increases, the radius of governor balls must also increase.