# How Does a Flywheel Store and Transfer Energy?

• wslukman
In summary: RPM.In summary, the conversation discussed the concept of transferring energy from mechanical to electric and the amount of energy stored in a flywheel at different speeds. The question also touched on the idea of wasted energy and where it goes in mechanical systems. The expert summarizer provided a link to a calculator for calculating kinetic energy and noted that energy can be converted to non-mechanical forms, such as heat, in mechanical systems.
wslukman
Flyheel the storage energy.

The transfer from mechanical energy to electric energy was equal.
The situation was, i got a 1/2 hp electric motor (EM) that can turning a 5 kg flywhell (∅ 28 cm) to 1500 RPM within 10 second. (connected by gear to each other)
question was:
1. at the 11 second, i turn off the EM, how much energy stored in flywheel until it stop turning.
2. at the 11 second, i turn off the EM, then the flywheel start to reduce it speed to 1300 RPM. At that moment, I'm starting turn on the EM again. How much energy from EM needs to turning and to regain the top speed of the flywheel (from 1300 to 1500 RPM).?

Thanks a lot for the answer.

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Thanks DennisN,

according http://www.botlanta.org/converters/dale-calc/flywheel.html
at 1300 RPM (5000 grams, dia = 283 mm) Disk KE (joule) = 463 j
at 1500 RPM = 617 j
is that mean, i need 617j-463j = 154 joule to regain the top speed.?

If something connected by the flywheel (blade of windmill or pump), energy from EM and energy that stored on flywheel was turn to a mechanical energy, if flywheel connect to none of subject, the energy are use to increasing and maintenance the RPM when flywheel reducing the speed, and some other are.. gone with the wind.? :)

back to question no 1, which expressed theory to answering that.?

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Where does "wasted" energy generally go in mechanical systems?

most are go/used to move "a thing", and finally get suck by "a thing". and disappear..
like energy mechanical we used to pushing a wall, and does the wall stored our energy? or disappear?
because energy can not be create or destroy, so it just flow... wasted, unused, disappear?
like a energy from wind before it get captured by windmill. it nothing but a wind .. I'm i right.?

i'm still need help for question no 1 :) please

You do not need energy to apply a force on a wall, if the wall does not move.

Energy does not disappear, but it can get converted to another (non-mechanical) type of energy. This usually happens everywhere in mechanical systems. Hint: you can feel it.

What do you mean with question 1, the energy stored at 1500 rpm? You calculated that value already.

again I'm using calculating using : http://www.botlanta.org/converters/dale-calc/flywheel.html
Input
Metric (gram, mm)
Mass = 15000
Diameter = 280
RPM = 1500

Output
Surface Speed (M/sec) = 21.99
Interia = 0.147
Disk KE (joules) = 1814.01
Is this the "only" stored energy on flywheel from 1500 RPM until it stop turning.? or rapidly energy output persecond (and the amount was decrease following the slowing revolution of the flywheel it self) ie. it gives out put 1754 joules at 1475 RPM

Centrifugal Force
(Kg) = 5258.07
(Newton) = 51828

wslukman said:
most are go/used to move "a thing", and finally get suck by "a thing". and disappear..
like energy mechanical we used to pushing a wall, and does the wall stored our energy? or disappear?
because energy can not be create or destroy, so it just flow... wasted, unused, disappear?
like a energy from wind before it get captured by windmill. it nothing but a wind .. I'm i right.?

i'm still need help for question no 1 :) please

no, that's not the answer mfb is looking for ;)

read this post of his again ... carefully :)

mfb said:
Energy does not disappear, but it can get converted to another (non-mechanical) type of energy. This usually happens everywhere in mechanical systems. Hint: you can feel it.

Dave

if it convert to (non mechanical ) type of energy. for mfb question the answer was heat. like when i using my weld machine, and yes too for most of friction betwen 2 or more mechanical thing, like friction on gear, V-belt, and even it not touching one to another, like friction betwen rotor and stator. The motor increasing their heat

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## 1. Where does energy come from?

Energy can come from various sources, such as the sun, fossil fuels, wind, water, and nuclear reactions. These sources provide the initial input of energy into our environment.

## 2. How is energy transferred from one form to another?

Energy can be transferred from one form to another through various processes such as conversion, transformation, and transfer. For example, solar energy can be converted into electrical energy through solar panels, and electrical energy can be transformed into mechanical energy in a car engine.

## 3. What happens to energy when it is used?

When energy is used, it is transformed into another form, and some of it is lost as heat. For example, when we use electricity to power our devices, the energy is transformed into light, sound, or motion, and some of it is lost as heat energy.

## 4. Can energy be created or destroyed?

According to the law of conservation of energy, energy cannot be created or destroyed. It can only be transformed from one form to another. This means that the total amount of energy in the universe remains constant.

## 5. How can we use energy more efficiently?

We can use energy more efficiently by reducing our energy consumption, using energy-efficient technologies and practices, and shifting to renewable energy sources. This can help conserve our natural resources and reduce our impact on the environment.

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