How Does a Flywheel Work? Explained in Simple Words
A flywheel is a machine that reserves rotational energy by resisting changes in rotation speed. The stored energy is proportionate to the square of the speed of the rotation. You can change the machine’s preserved power by applying a torque to grow or reduce its rotational speed. A machine or a vehicle loses the momentum every time it slows down or stops. A flywheel makes up for that lost momentum by supplying from its reserved power. In this brief guide, we will discuss how does a flywheel work and what does it do.
What are the Functions of a Flywheel?
Before delving into the working principle of a flywheel, it’s important to know their functions. It is used in almost all types of automobiles including race cars, trains, and buses. It mainly serves these functions in most vehicles:
- Keeping the engine in motion by providing mass for rotational inertia
- Bringing balance to the crankshaft with its carefully measured weight
- Helping the engine with the starter ring to get it started
- Connecting the engine and transmission for transferring power
In the past, they used to have a large diameter with spokes and a bulky metal rim. However, the modern units are more compact due to being made of composite or carbon fiber materials. You have to push the wheel hard to set it in motion.
How Does a Flywheel Work?
A flywheel is a weighty wheel that requires plenty of force to rotate on its axis. When the wheel is in motion at a high speed, it will keep spinning unless you stop it by applying lots of force. When it rotates, it preserves a great amount of kinetic energy that it later uses to power up a vehicle or machine at the time of starting the engine or speeding up.
How does a flywheel work for storing the energy? Well, you can compare it to the mechanism of a mechanical battery. Whereas the battery stores the energy in a chemical form, a flywheel preserves the power in the form of movement or kinetic energy to be precise.
A flywheel will be able to store more energy if it spins at a higher speed or has a higher moment of inertia, which means bulkier. However, it always works best when you spin it faster rather than increasing its mass. For example, a wheel will produce twice as much energy than the one that weighs half of it, given that both are spun at the same speed. On the other hand, spinning the lighter wheel twice as fast will quadruple the amount of stored energy.
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For this reason, it’s always better to use lighter, high-speed wheels rather than the units having a massive weight. Also, compact flywheels make practical sense in racing cars because they need to be as light as possible to run at high speeds.
How does a flywheel work when you keep increasing the speed? It is not possible because there is a point when the wheel material won’t be able to handle the force and smash into fragments.