I just blew some wind at a hand held DC fan to see what electricity could be generated by running the DC fan in reverse by blowing wind at it. I surprised myself with a reading of 0.25 Volts and 30 mA, generating power of approximately 0.01 Watts. (rounded up)
Does anyone know if this is indiciative of the level of power I could expect if I tried this experiment on a 12V DC car fan?
Just a guess please....
2007-05-23 08:50:07 · 5 answers · asked by James 6 in Science & Mathematics ➔ Engineering
In principle, a DC motor can also be used as a generator, but not very efficiently.
There are rare cases where this has been put into practice, and compromises have to be made on the motor's design.
The reason is that a motor is designed with the objective to deliver as much power as possible with as little electrical power as possible. A wind turbine (generator) is designed to deliver as much electrical power as possible, with as little torque as possible.
Also, to make your idea kind of "useful", you have to blow very hard in order to have the motor spin very fast. What they do in reality (with wind turbines) is that they have very large "propellers", so there is a large force but low revolutions. This is then sent to a gear box which increases the R.P.M. high enough for the generator to supply a decent electrical power.
2007-05-23 14:23:41 · answer #1 · answered by Marianna 6 · 0⤊ 0⤋
A motor is used to drive something.
If you have something driving a motor, it will produce power.
This, in a way, is the principle of a wind turbine driving a generator. If the generator is connected up as a motor, it will drive the turbine.
(I know this to be true, because, in North Wales (UK), a hydro-turbine driving a generator during peak electrical periods, is, at low peak periods, used as a pump driven by the generator as a motor, to return the used water from a lower reservoir back to the higher reservoir that provided the driving force in the first place).
2007-05-23 16:11:11 · answer #2 · answered by Norrie 7 · 0⤊ 0⤋
I tried that with a motor once - I think it was a windscreen wiper motor and we had a rotor blade on a pole! Not much useful power. Try a alternator from a car - and attach it to a car battery through a rectifier and let us know what currents you get! An alernator could also be put through a transformer to give a useful voltage - to charge your laptop or something. You could invent a portable windmill for people with flat car batteries! lol
2007-05-23 16:02:24 · answer #3 · answered by Mike10613 6 · 0⤊ 0⤋
The 12VDC fan may not have a permanent magnet motor, in which case you get no power output. Otherwise, about 0.01 W (rounded up).
2007-05-23 16:06:40 · answer #4 · answered by Helmut 7 · 0⤊ 0⤋
that depends on how many banes you have eaten.
2007-05-23 15:54:29 · answer #5 · answered by capa-de-monty 6 · 0⤊ 0⤋