Difference Between Flywheel and Governor?

Basically, both the flywheel and governor are used to accomplish two different goals that is to regulate fluctuations of energy or to regulate constant speed. In this article, we are going to discuss what’s exactly the difference between flywheel and governor, their applications and functions.

Let us first start by knowing what is flywheel?

What is Flywheel?

Difference between Flywheel and Governor

Basically, a flywheel is a rotating disc or wheel, spinning about its axis of symmetry. Due to rotational motion of flywheel it generates rotational energy. As the angular or rotational speed of flywheel increases, its rotational energy also increases. As we know that the rotational energy of flywheel is directly proportional to the square of its speed. In this way, due to increasing energy flywheel acts as energy storage devices such as battery. This energy is released by flywheel when required by applying a torque to a mechanical load.   

Why We Need a Flywheel?

Due to torque fluctuations there are many variations in the speed of the shaft. Therefore, to reduce such variations in energy there is a need of flywheel. When the energy is needed to supply continuously but it is not available, the energy is available periodically. In that case we use flywheel. It stores the energy (rotational Energy) when available in excess and supply that energy when it is not available. So In this way it maintains the continuous supply of energy and eliminates the problem of energy fluctuation.

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Applications of Flywheel

  1. They are used in small scale generators where Internal combustion engines are used.
  2. They are used as batteries in aerospace industry due to their energy storage capability.
  3. In electric vehicles, they perform as power boosters.
  4. It is used in automobile engines to remove fluctuation of energy.

Let us take a glance in knowing the second part of our discussion i.e. what is governor?

What is Governor?

Difference between Flywheel and Governor

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We can call governor as speed control device as its main function is to control the mean speed regardless of load variations.

Let us understand exact working behaviour of governor at a glance:

As we know that as the load on engine increases, its speed decreases. Therefore, it is mandatory to increase the supply of fuel. In the other case, as the load on engine decreases, its speed increases which in turn require less supply of fuel. So, the governor automatically maintains the supply of fuel despite of varying load conditions and this keep the mean speed constant. The governors are mainly classified as centrifugal governors, Pickering and inertia governors.

Application of Governor

  1. Governors are mostly used in steam turbines and water turbines.
  2. They are used to limit the rotational speed of internal combustion engines.
  3. Today, BMW, Audi, Jaguar, Mercedes all have speed limiters that protect engines from damage due to excessive rotational speed and thus limit the top speed.

Difference Between Flywheel and Governor in Tabular Form:


                            FLYWHEEL                       GOVERNOR
1 Flywheel is used to prevent fluctuation of energy and does not maintain a constant speed. Governor is used to maintain the constant speed, whenever there are changes in load.
2 Generally, flywheel is a heavy part of the machine. Governor is a lighter in weight than flywheel.
3 It is a rotating component. It is a non-rotating component.
4 Energy generated due to flywheel is directly proportional to the square of its angular speed. There is no such proportionality or equation in a governor.
5 As there are energy variations in engines, a flywheel results in a maintaining a constant speed of crankshaft in each cycle by supply the required energy to the preparatory stokes (other than power stroke). As the load on engine increases, the speed decreases. This increases the flow of fuel for regulating constant speed.
6 While storing energy, rotational speed increases and during supplying of energy speed decreases. Under all fluctuating load conditions mean speed is regulated.
7 The moment of inertia of flywheel is very large. The moment of inertia is very small.
8 It doesn’t control the fuel supply. It controls the fuel supply.

In this article we have learnt about the basic difference between flywheel and governor. If you found anything missing than let us know through your valuable comments. Do share this article if it add some knowledge to you. Thanks in Advance.

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