would this work for a homemade generator?... like getting a dc motor and turning it in reverse ?

instead of spinning the moro by connecting it to a battery spin it on the spindle that turns? would it work

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kelseymh8 years ago
Speaking very generally, yes, that would work. The basic structure of an electric motor and a generator are identical: coils of wire surrounded by a magnetic field. If you run current through the wires, it reacts against the magnetic field, producing a force that makes the thing spin. Conversely, if you spin the coils through the field, that induces a current.

However, with actual motors you might buy or remove from some device, there is a good chance that it won't work:

  • Some motors use electromagnets (that is, some of the input power goes to creating the external magnetic field) instead of permanent magnets. Without a power source, there's no field and hence spinning the motor won't induce any current.
  • Some motors have built in circuitry or mechanicals which prevent manual turning of the spindle from producing a "backflow" current.
The only way to be sure in your specific case is to get the specifications for the motor you plan to use. Typing the model number into Google is a good start. Asking here without doing a proper and intelligent Web search is not a good start.
sharlston (author)  kelseymh8 years ago
ok a cheap circuit motor is what im using the ones i got with s a cheap kit when i was 7 there really cheap and i wouldnt of thought it would be anything special so what do you think?
I would agree with you -- those little motors (one or two cm across, right?) don't have room for much fanciness. The best thing to do is exactly what you talked about already: hook the leads up to an ammeter (current, not voltage) and just spin the thing to see what happens. Good luck!
sharlston (author)  kelseymh8 years ago
ye youre right with the dimensions thanks ill try
jj378 years ago
in short? yeah what type of motor is it? (please reply) just put a diode on the positive lead (with the proper specs) facing away from the motor so that the energy you just created does not get used to turn the motor in the opposite direction. you may want some gears to make low rpm high torque into high rpm low torque depending on the motor and how you turn it.
sharlston (author)  jj378 years ago
its a cheap motor i got with a circuit kit do i need the diode ?
jj37 sharlston8 years ago
well the diode allows the energy to flow in only one direction so anything with a battery or capacitor yeah you would need it, but if you wanted to power an Incandescent light bulb without any power regulation no it would run just fine without the diode.
sharlston (author)  jj378 years ago
ok i was just gonna hook it up to a voltage tester to see if it worked would that be ok and whats the voltage im going to get on it by spiining it with my fingers also would a bigger or smaller motor be better becuase i have one from a cordless angle grinder
jj37 sharlston8 years ago
well the bigger the motor usually means more power because of more powerful magnets and more coils so you make get more wattage out of the bigger one at the same rpm
jj37 jj378 years ago
if you want to use the power you created to power something like a tv or any thing that plugs into a wall you will probably charge a 12v battery and use an inverter connected to the battery to power it