# GATE Questions & Answers of Flywheels and Governors

## What is Flywheels and Governors ?

Flywheel is a mechanical device used to reduce fluctuation of speed of the output shaft during various strokes of a cycle. It acts as a reservoir of energy which stores the excess energy during power stroke and releases it during idle stroke. Governor is a mechanical device used to maintain the mean speed of the engine within certain limit, when there are variations in load. It maintains the mean speed by increasing or decreasing fuel intake.

## What is the Weightage of Flywheels and Governors in GATE Exam?

Total 8 Questions have been asked from Flywheels and Governors topic of Theory of Machines subject in previous GATE papers. Average marks 1.75.

For the same material and the mass, which of the following configurations of flywheel will have maximum mass moment of inertia about the axis of rotation OO′ passing through the center of gravity.

The torque (in N-m) exerted on the crank shaft of a two stroke engine can be described as T = 10000 + 1000 sin 2θ – 1200 cos 2θ, where θ is the crank angle as measured from inner dead center position. Assuming the resisting torque to be constant, the power (in kW) developed by the engine at 100 rpm is __________.

Consider a flywheel whose mass M is distributed almost equally between a heavy, ring-like rim of radius R and a concentric disk-like feature of radius R/2. Other parts of the flywheel, such as spokes, etc, have negligible mass. The best approximation for α, if the moment of inertia of the flywheel about its axis of rotation is expressed as αMR2, is _______

Maximum fluctuation of kinetic energy in an engine has been calculated to be 2600 J. Assuming that the engine runs at an average speed of 200 rpm, the polar mass moment of inertia (in kg.m2) of a flywheel to keep the speed fluctuation within ±0.5% of the average speed is _______

Torque and angular speed data over one cycle for a shaft carrying a flywheel are shown in the figures. The moment of inertia (in kg.m2) of the flywheel is _______

A flywheel connected to a punching machine has to supply energy of 400 Nm while running at a mean angular speed of 20 rad/s. If the total fluctuation of speed is not to exceed ±2%, the mass moment of inertia of the flywheel in kg-m2 is