Flywheel | Function , types , Advantages , Application

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.
• To reduce the power capacity of an electric motor or engine.
• Applications of the flywheel can be broadly divided into two parts based on the source of power available and the type of driven machinery.

Work of flywheel

1. When the power available at a variable rate but is required at a uniform rate. For e.g. the machinery is driven by the reciprocating internal combustion engine.
2. When the power is available at a uniform rate but we need it at a non-uniform rate. For e.g. power required in punching press. In this case, we need sudden power at punching stroke.

Types of flywheels

On the basis of angular velocity, flywheels can be divided into two types.

1. High-Velocity Flywheel

The angular velocity of these type of Flywheels comes between 30000 rpm to 60000 rpm which may even be adjusted up to 100,000 rpm. They contain magnetic levitation bearings and need less maintenance. They are lighter in weight if compared size/capacity wise to low-velocity flywheels. They are costly in comparison to Low-velocity Flywheels.

2. Low-Velocity Flywheel

The angular velocity of these type of Flywheels comes up to 10000 rpm. They are bulky and heavy if compared to high-velocity Flywheels. They need periodic maintenance and does not use magnetic levitation bearings. Their installation needs special concrete construction to support its weight. They are cheaper in comparison to high-velocity Flywheels.

Difference between flywheel and governor

Many people confuse between flywheel and governor, but they are totally two different things. Here are some differences between them.

• A flywheel is used to mitigate cyclic fluctuations in available energy but a governor is used to adjust the supply of fuel as per the load.
• The energy stored in the flywheel is kinetic which is 100% available but the governor mechanism involves friction.
• The flywheel is not used when cyclic fluctuation of energy is small or negligible.
• While a governor is necessary for all the types of engines because it limits the fuel supply as per demand.
• If we have constant load then the governor will remain idle but due to cyclic fluctuations in energy available, the flywheel will always work.
• Governor has no influence in cyclic fluctuations in energy and flywheel has no influence on the mean speed of an engine.
• Governor controls mean speed of the engine and flywheel controls cyclic fluctuations in energy.

• Less overall cost
• High energy storage capacity
• High power output
• They are safe, reliable, energy efficient, durable
• It is independent of working temperatures
• Low and inexpensive maintenanceHigh energy density

Limitations of flywheel

1. They can take a lot of space
2. They are expensive to manufacture
3. The building material is always a limitation for it

Applications of Flywheels

• In reciprocating internal combustion engines
• In wind turbines
• In the locomotive propulsion system
• In satellites to control directions
• In Mechanical workshops
• In punching machines

Mechanical Subjectwise Basic Concept Notes ,Articles

Sachin Thorat

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

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