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This might be a silly question but is it at all possible to use a small electric motor with a small battery to turn a small generator then connect the generator to a slightly larger electric motor to turn a slightly larger generator and so on building the chain up till you get to the desired power output.

Thank you for the advice

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    \$\begingroup\$ If the desired power output is less than you're putting into the smallest motor, yes it's hypothetically possible. \$\endgroup\$ – Brian Drummond Mar 7 '18 at 16:23
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    \$\begingroup\$ I'm voting to close this question as off-topic because this site does not address violations of the laws of thermodynamics. n.b. no it is not possible. \$\endgroup\$ – RoyC Mar 7 '18 at 16:26
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    \$\begingroup\$ You can make a small fortune from this idea, if you start with a large fortune \$\endgroup\$ – Dirk Bruere Mar 7 '18 at 16:37
  • \$\begingroup\$ So, ultimately, the small battery powers the entire world. \$\endgroup\$ – Chu Mar 7 '18 at 16:45
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    \$\begingroup\$ You missed the version where a small generator drives a large generator, and some of the second generator's output powers the motor which drives the first, leaving a surplus of power available for free. Sorry to be flip, but what you are proposing is called a Perpetual Motion Machine. And those don't work in this part of the space-time continuum. \$\endgroup\$ – WhatRoughBeast Mar 8 '18 at 1:01
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No. You're trying to violate the Law of Conservation of Energy, which is impossible. What will happen is your small generator will produce less power than you're feeding into the small motor, say 60%. Then the next generator will produce say 60% of the power from the next motor, and so on and so forth until you waste all of the power you put in as heat. Even if your generators and motors were perfect, you can only get as much power out as you put in.

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Many people don't realise that when a load is placed on an electrical generator that it becomes more difficult to turn. You can demonstrate this to yourself in a couple of ways:

  • Spin a bicycle wheel with a generator (often erroneously called a dynamo) with the light off. Then short-circuit the generator terminals and try again. The resistance to rotation will be high.
  • Start your petrol or diesel engined car (or someone else's) and let the engine idle. Turn on the headlights, fan, wipers, demisters, etc. Listen to the engine speed drop as the alternator takes up more load and provides more rotational resistance to the motor.

What you have suggested is called a "free energy scheme". The web is full of them. When you see ideas such as this a big red warning should flash in your brain.

The amount of energy out of the generator will always be less than you put in.

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This is known as a Motor-Generator set or MG set.

With lower CO2 demands large motor designs (>>10kW) now have premium efficiency standard (IE3) and premium efficiency motors (PEMs) that can reach 96% near 100kW. Thus a 4% loss minimum at optimal loading for each component.

For tiny motor generators, you can expect much more losses. have fun with it. It demonstrates you awareness to energy conversion for mechanical stored energy and electrical generation of energy, voltage, current and frequency but losses are unavoidable. Its a Law of Physics. Many examples of over-unity are examples of measurement errors of (peak to Rms) and ignoring the stored energy in magnets which also contribute and get depleted.

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