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Ideal coil size for a low wind turbine.

  1. Feb 3, 2014 #1
    I can't find anything I can make heads or tails out of so if you guys can help I thank you.

    I would like to design a wind turbine and be able to get as much power as I can out of each of it's coils. If I start with a magnet that is 1.1811" in Diameter and it is .125" thick with a grade of N52 and I only allow for a air space of .0625" between the magnets and coils what would be the ideal coil size / wire gauge to use and so forth.
    I can't find the exact specs for that particular magnet but from looking at another very similar one the spc's for the magnet would be approximately as follows;
    Br: >=14,800 Gauss
    Bhmax: 52MGOe
    Surface Field: 918 Gauss

    Given I make the inside of the coil the diameter 1.1811", (the diameter of the magnet) what
    are the other specs I should use to make the coils if I want it to generate power at a low wind speed. I'm thinking it would not be able to go much faster then 300rpm. (my best guess)

    So in other words how many loops across should I go with the coil and how many layers of coils should I go and with what gauge of wire.

    Also given 300rpm how many volts / amps / watts would the finished coil put out.

    Thanks and sorry if I'm missing something here, I'm no physics expert by any means.
  2. jcsd
  3. Feb 4, 2014 #2
    It all depends on what you want to do. I've built one a couple of years ago using the same pretty much the same size and type magnets and I suggest to try a search on building wind turbines. Don't expect to get more than about 12 volts and 1 amp out of it if your using it for battery charging at that low a rpm speed.

    I used 400 turns of 30 gage magnet wire for the coils. 9 coils with 12 magnets per outside rotor.
    You can see it here: http://www.packratworkshop.com/wind4.htm
    I was driving mine with a 3' Savonious type rotor maxing out about 450 rpm on a good windy day. I'm in Wilmington NC and we don't get a lot of wind here along the coast except for morning and evening breezes on and off the ocean.

    This would be a good place to start for more information: http://www.scoraigwind.com/index.htm
    That guy probably knows more about that type of wind turbine alternator than just about anyone you might run across.
  4. Feb 4, 2014 #3
    My fault I should have shown how I was planing on laying out the coils. As you can now see
    in the picture I attached the coils are represented as those circles below. I have the turbine
    lifted away from the coils so you can see them but when done the turbine will float just above
    the coils using a magnetic levitation in the middle and I will use a shaft to stabilize the whole thing.
    I'll use weight to adjust to get the exact levitation level correct so the turbine with the magnets floats just above the coils of wire. Oh and by the way according to the wire guide 1AMP on 30AWG
    wire would break the code / thus burn your wire. That very thin wire is only rated for .86 AMPS.

    Hope this makes sense.

    Attached Files:

    Last edited: Feb 4, 2014
  5. Feb 4, 2014 #4
  6. Feb 4, 2014 #5
    Your setting up a standard design for a typical turbine.
    Yes, I know that wire I used was small and what it is rated for. It was the only way I could to get the coils flat enough for the thin magnets to have any worthwhile affect. I wasn't suggesting you do the same.

    I just told you how mine was setup, that's all. My turbine normally put out about 1/2 amp in operation. We don't get a lot of wind here, it's a class 1 area and I wasn't too worried about burning out the coils as this was nothing more than a demonstration setup to show a small wind turbine would work here even if not well.
    Last edited: Feb 4, 2014
  7. Feb 4, 2014 #6
    Very curious to the one reply with the guy who made one with high volts, where on earth did you
    get a inverter that could take the high AC voltage and convert it to usable AC voltage for the grid? Been looking my self and can't find a inverter like that.

    They are N52's so they should ideally give a lot of electric current for their size, this is what I I'm thinking. I realize Farady's law would help in making the calculations but I can't figure out what the symbols stand for.

    for example what dose the triangle mean.? ∇
    These symbols are part of my biggest problem.

    I also am not sure how to use the formula to figure out the watts I would finally get per revolution.

    If someone could give a demo example on how to use the formula that would really help.
  8. Sep 27, 2015 #7
    N = -1 * (-V/change in (( tesla * area meters squared)/ seconds))
    Turns= -1 (-V (( magnet strength * magnet size ) / magnet speed))

    Flat coils work best as the gause penetration is better
    More winding higher voltage
    Faster RPM gives higher voltage
    Thicker wires gives higher amperage
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