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Wind turbine for low speed winds

  1. Jul 13, 2009 #1
    I'm looking for a summer project and I'm thinking of building a wind turbine to generate additional power for our home. I want it connected to the grid so that it runs our meter backwards for times where we arn't using more power than we generate (on vacation or something, electric company has a net metering program), but I also want it connected to a back up battery system so our fish don't die when electric company gets bombed by china or something.

    Unfortunately, I don't really have much electrical knowledge. It's the one area in science that I really struggle in.

    I know the basic idea of a wind turbine. The wind spins some blades which turns a alternator which generates power. I don't, however, know exactly how to build these things. Like how exactly do you shape the blade so that it products the most centrifugal (I also struggle in the spelling department) force from the wind?

    How exactly do you build a alternator and how exactly do you harness the power generated? I know the alternator consists of rare earth magnets and some coils of wire and one of those two is spun by the wind which cuts flux lines generating power, but that's about as far as I know. I'm not exactly sure how to build the rotor and stator.

    Once I get the alternator generating power, how do I hook this to a backup battery system, and the electric grid? I've read websites saying things like to run the alternator to a charge controller which is hooked to some diodes and stuff, but it doesn't really explain the function of each part and that just makes me feel like a script kiddie. I don't feel I could really say I built if I just copy what they are doing without understanding it. It's like saying I drew an awesome painting when I just used crayons in a coloring book.

    Another thing on the alternator that I don't know is exactly how to place the magnets and coils. I mean how should they be arranged to produce the most power from a single rotation or what not?

    I would like to build all this from scratch, so that I can learn. Kind of off topic, but while working on this project (if it's not too expensive) I would love to buy a CNC mill (or would it be a lathe I need?) and learn how to use one of those. If anyone knows a cheap good one (that can mill both soft and hard materials) I'd love to hear about it.
    Last edited: Jul 13, 2009
  2. jcsd
  3. Jul 13, 2009 #2


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    Staff: Mentor

    This is not a project that can be built from scratch. The components are precision engineered and constructed, representing thousands of hours of engineering effort to design and hundreds of hours of manufacturing time on precision manufacturing equipment to produce. I recommend you start looking at what manufactured systems look lik.
  4. Jul 13, 2009 #3
    What do you mean? There are lots of websites with instructions on building turbines from scratch, but they just don't explain everything. That just say do this and this, but not why.

    Like here:

    http://www.build-a-windturbine.com/partmaking/makingparts.htm [Broken]

    Here's another site:

    Last edited by a moderator: May 4, 2017
  5. Jul 13, 2009 #4
    Building a functional mains coupled wind turbine is not like restoring a hot rod. It takes an exceptional amount of time, effort, and is extremely challenging. If you want to build a small one for the hell of it to recharge a battery or something then its certainly doable. But if you have little to no electrical knowledge and want to actually hook one of these things up to your house, then tell your spouse/mother to clear a space on the mantel for your Darwin Award.
  6. Jul 13, 2009 #5


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    Staff: Mentor

    You also said in your post that you want to build yourself a lathe: you don't have the equipment you need to machine these parts! The guy in the first link has his own CNC machining equipment! Are you a professional machinist?

    Without wading through the entire thing, I don't see anything on the second page that implies that level of "from scratch"
  7. Jul 13, 2009 #6
    Reread the post. I said BUY a cnc mill. Not build. although I've found guides to build cnc mills I would rather have something of higher quality. I have experience programming a cnc lathe.

    Also the mill the guy in first link is using is home-made. There are instructions to build it at cncsource.com I believe.

    I just need a more detailed explanation on how a alternator works. Do the magnets rotate in front of the coils? Around them? These are the kinds of things I don't know.
    Last edited: Jul 13, 2009
  8. Jul 14, 2009 #7
    I don't see anything in these links I couldn't build in my laudry room. Skill is another matter.
  9. Jul 14, 2009 #8


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    Staff: Mentor

    You have a machine shop your laundry room? :confused:
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