Is it possible to supply a motor with the supply produced by an alternator that the motor turns .?

Question

After starting the motor from an external source, the motor turns an alternator which produces electricity that is used to supply the motor permanently.The alternator,s output being >motor input.

Answer 1

Not sustainable

Would need to be exactly 100% efficient

Energy losses due to component friction, air resistance,  heat losses, electrical cabling resistance, giroscopic effects, even the rotation of the earth would prevent 100% efficiency being achieved

Answer 2

"But, it you made it out of a frictionless bearing using a superconducting material.... nope!"

Eugene, you are wrong! The problem is that as motors turn, they create back-current, that is they require more power to turn than they put out:

A 1kW output motor requires more than 1000 watts of electrical energy input, regardless of friction and heat losses.

An alternator (generator) behaves in the same way, because of internal inefficiencies not relatesd to friction or heat losses. To get 1000 W of power out of an alternator, you have to put more than that into it.

Answer 3

this is what a 'waste of energy machine' would look like.

as soon as the external supply is cut it will slow down to zero very soon, maybe straight off.

Answer 4

Yes, but it will eventually slow down and stop, because the wires in the motor and alternator have resistance - which converts current into heat.  Eventually, all of the electricity will be converted to heat, and dissipate into thin air.

Answer 5

For alternators output to be greater than the motors input would require an efficncey of at least or greater than 100%. i.e. the procees would be what is termed reversible, in which the entropy of the procees would decrease. This defies all laws of physics as currentlly known.  It's like trying to get water to run a turbine, then get the water to run uphill, to flow back down and drive the turbine again.

Answer 6

The motor would have to be 100% efficient - zero friction, zero heat produced and zero internal resistance.

The generator would also have to be 100% efficient with the same restrictions as the motor.

None of these conditions can be realized in practice, only in your imagination.

Answer 7

Of course.  All you have to do is get a motor that puts out more power than it consumes.  Good luck with that.

Answer 8

No, you cannot get anything for nothing. Resistances come into it for one thing.

Answer 9

Why that sounds like perpetual motion.  In every system there is loss.  Loss to friction, loss to sound, heat, etc.  Thos losses eventually take their toll and the system will grind to a stop.  But, it you made it out of a frictionless bearing using a superconducting material....  nope!

Answer 10

In an ideal world yes, it would be possible however....

In the system there are energy losses and these energy losses make the idea fail.

For example, there is friction in all the bearings which loose energy, wind resistance of the rotating parts, electrical losses in the copper windings... lots of little bits that make the system fail.

If it was ideal then the copper would have no resistance, the bearings wouldnt slow the machine and there would be no wind resistance (whole system is in a vacuum)

So no it cant work

Answer 11

This is called a perpetual motion machine.  Charlatains have been pedling stuff like this since the start of the industrial revolution.  Now with energy prices rising drasticaly you can expect many more of them to come crawling out of the woodwork.

Answer 12

No, perpetual motion is a 'Dream Machine'.

Answer 13

In fact, it wouldn't even coast longer than a few turns.  The system would absorb all the momentum in a few seconds.  What you are describing is a type of perpetual motion machine, and the laws of thermodynamics prevent such things from existing.

The French Patent Office stopped issuing patents for Perpetual Motion machines more than 300 years ago, and all other patent offices followed suit.

For more information, try an Internet search on "second law of thermodynamics" or "perpetual motion."

Answer 14

Thought you discovered a perpetual motion machine, didn't you? Wrong again.