Correct Answer - Option 4 : The coefficient for speed fluctuation in a flywheel is not limited purely by physical constraints.
Explanation:
Flywheel
A flywheel is a heavy rotating body which acts as a reservoir of energy. It acts as a bank of energy between the energy source and machinery. Energy stored in a flywheel is in the form of kinetic energy.
Functions of flywheel
- It is used to store energy when available and supply it when required.
- To reduces speed fluctuations during each cycle.
- To reduce the power capacity of electric motor or engine.
Fluctuation of Energy of the flywheel is given by,
ΔE = Iω2Cs
where, I = Moment of Inertia, ω = Angular velocity, Cs = Coefficient of fluctuation
From the above, ΔE ∝ I
Therefore, the flywheel will be large for high fluctuations in energy.
And \(I \propto \frac{1}{\omega ^2}\)
Therefore, for a high-speed engine, the flywheel will be smaller.
Coefficient of fluctuation of speed (CS):
\(\begin{array}{l} {C_S} = \frac{{Maximum\;fluctuation\;of\;speed}}{{Mean\;speed}}\\ {C_S} = \frac{{{\omega _1} - {\omega _2}}}{\omega } = \frac{{2\left( {{\omega _1} - {\omega _2}} \right)}}{{\left( {{\omega _1} + {\omega _2}} \right)}} \end{array}\)
Therefore, the coefficient for speed fluctuation in a flywheel is not limited purely by physical constraints.
