Type of stepper motor to use in wind generator

Discussion in 'General Electronics Chat' started by henry newton, Mar 23, 2010.

  1. henry newton

    Thread Starter Member

    May 5, 2008
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    Hi
    i am working on building a small wind generator using stepper motor. I need a stepper motor that is 1.8 degree and can generate up to 12v, 0.5A. What i need from u guys is suggestion on the make or model to buy.
    Thank you guys.
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    I've never heard of using a stepper motor as a generator. Regular DC motors, but not steppers. I'll be interested in other replies to this.

    This isn't the right forum for this. A moderator will be along and move it, I suspect.
     
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    BOING!!!! :eek:
    Stepper motor as a wind generator.
    Buddy , Are u sure about this?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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  5. AlexR

    Well-Known Member

    Jan 16, 2008
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    Why not?
    A stepper motor has coils and magnets so yes it will generate electricity. Just how efficiently it will do it is another matter.
    I've never tried using a stepper as a generator but doing Google on "stepping motors as generators" brings up plenty of hits. However I suspect that you would be better off using an old auto alternator since it is actually designed to generate electricity rather than consume it.
     
  6. retched

    AAC Fanatic!

    Dec 5, 2009
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    A stepper motor is a bad idea. You will only get a pulse on each pole for a 1/4 of the turn. Small coils are used and reversed polarity to HOLD the weight and to step more accurately. Alternators work better because the generation on each phase is done for the entire rotation.

    For weight to power, it is not a very efficent idea.
     
    Last edited: Mar 23, 2010
  7. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Gratefulway
    Please do not hijack others threads.
    You can post ur question in the appropriate forum
     
  8. davebee

    Well-Known Member

    Oct 22, 2008
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    I've heard of using steppers as generators, but have never done it on a large scale.

    I've wired two steppers in parallel to run the demonstration of rotating one stepper by hand and seeing the other stepper rotate in sync; that's generating a small amount of power.

    So I'm sure it would work to some extent.

    But steppers are designed to do a particular thing well - run to a known position. It may be that they'll have higher eddy current losses or something if run continuously and fast, as compared to a generator that was designed as a generator.

    If the stepper gets hot while generating then it's wasting power, but if not, and if it's able to generate enough power to satisfy your project, then I don't see any problem with this idea.

    But I have no idea what make or model would be best to buy.

    Actually, I'd suggest getting the cheapest possible used or surplus stepper motor to start with, and do some experiments with it. Drive it with an electric drill and test its power generation and overall performance before desiging the full wind system.
     
  9. gseattle

    New Member

    Apr 29, 2010
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    I used diodes for the three wires from the coils for one of these: http://www.mavin.com/index.php/products/moog-12-vdc-high-performance-motors-10-for-1-price brushless motors to try it as a generator, its rotor has neodymium magnets. At about 2500 RPM it put out 8.3 volts open circuit, and/or a little under 4 amps through a 1 ohm resistor.

    Nice little test that was disappointing though not surprising.

    Motors are great for quickie generators temporarily in a pinch and in certain applications, however, correct me if I'm wrong, they all suffer from the following problem:

    As a motor, the coils develop a magnetic field that is then channelled (focused, so-to-speak) in the iron core (or "pole pieces") for fairly precise timing interaction with the permanent magnets (when applicable).

    As a generator, as the rotor spins, the magnets induce current in the coils, however, the presence of the iron pole pieces means that a large amount of the magnetic flux is wasted since it is channelled/focused to travel through that iron (side-stepping the coils), so a significant portion of the magnetic flux never encounters the coils at all, doesn't even know they are there.

    There's a lot of DIY building of wind generator generators out there, people building them on their own. In those, there would be no iron next to the coils to be diverting flux *around* or past or away from coils, instead iron can be best used in that case to just encourage/direct the return path back to the other side of the magnets (if that's clear at all).

    Or picture a 'C' shape (made of iron) with coils at each end, and magnets on a rotor passing through that gap, that would be pretty efficient.

    Unfortunately with a motor being used as a generator, it's a little more like having a coil wrapped around the left side of the C.

    There's probably a better analogy. If anyone knows of a good writeup on this, I'd like to read it. Thanks.
     
  10. Hasan Yahya

    New Member

    Nov 10, 2015
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    Let me give you an answer generally, or theoretically. Maybe you no need to buy such device if is not available in the market, as alternate choice you can create it by yourself. The device my intention is transformer either step-down or step-up transformer. In the case your problem (lower voltage) you can create step-up transformer (higher voltage). Therefor, you can use equation Vs/Vp= Ns/Np. Is it useful ?
     
  11. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    We can wait for the OP to come back to answer you.
    Till then I will try Netflix.
     
    tcmtech likes this.
  12. dendad

    New Member

    Feb 20, 2016
    17
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    I've used a small stepper for a wind generator, but just for fun. It had 6 x diodes wired up as a 3 phase rectifier bridge and just ran some LEDs on it in the garden. make sure the front of the motor is protected from water getting in.
    Look for a stepper from an old printer as a start to see what you can do with that.
    What are you trying to run from this? Wind is not very reliable and if you need 12V at 0.5A all the time you will need to aim much higher power and have battery charging too.

    A quick Google came up with these...

    http://www.thebackshed.com/Windmill/articles/GettingStarted.asp

    For bigger generators, a very popular "stepper" or Brushless DC Motor is the Fisher and Paykel Smart Drive motor. There is a great deal of info on the net about them...

    http://www.thebackshed.com/windmill/FPRewire.asp

    www.boatdesign.net/forums/.../103523d1445650692-making-wind-turbine-fpall.pdf

    This is just a start. Have fun :)
     
    Last edited: Oct 25, 2016
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