Instructables

Step 16: Conclusion and a Plea For Help

That's it! You have a crazy renewable energy source of perhaps dubious usefulness. BUT there is a lot more that can be done. I'd like to throw out a few suggestions to the crowd for thing to try:

  • double up the magnets and coils. Put one set on the bottom and one on the top. Wire the DC output of each in serial and double the voltage. Hopefully.
  • bigger, badder coils. Really see if you can up those wraps to a crazy degree. I think that's the key.
  • take a look at the mintyboost USB charger (http://www.instructables.com/id/EGBQJPLCB2EP287KTZ/). I've spoken with the inventor herself, and she says that the circuit that drives it can work with input voltages between 1.5 and 4.5 volts, with the most efficiency in the middle of that range. It produces steady 5V power off of two AA batteries (which are only 2.4 to 3.0 volts). If you have this project with that one, do you get a wind-powered iPod charger? Try it and let me know.
  • try a different bearing. My big thing is to use as simple and readily available parts as I possibly could, so I swore off fancier parts. You have no such limitation. I have it on good authority that skateboard bearings would be great for this. Or some other kind of bushing. Let me know what you come up with (especially if it's hacky, cheap, and better than what I've done.)
  • Small lazy susans are available at art and sculpture supply stores that might also make good bearings.
  • Made a bunch of these turbines? What happens when you wire them together in series? Can you make a "Pleech" farm?
  • There's another more efficient Vertical Axis Wind Turbine design called the Darrieus Turbine (http://en.wikipedia.org/wiki/Darrieus_wind_turbine). It uses lift instead of drag. If you have an easy way to modify this turbine into one of those, drop a comment down here.

What I'd really love is for this to be the first (well, second) version in a long series of continually improving small turbines, the goal of which would be to power small devices (phones, sensors, art projects installed on public buildings, etc.) So, what did I do wrong? And what could be done a whole lot better? If you have answers, let us know. Hopefully, we can "crowd source" a way to make a pretty decent, and fairly cheap, wind powered generator.
 
Remove these adsRemove these ads by Signing Up
VoltisArt1 year ago
One thought that's come to mind regarding bearings -- this is another place magnets can help. I looked around and the easiest source seems to be computer case fans. Very low friction. Then it occured to me that the fan itself, (minus blades for higher speed, though the cooling factor may benefit the workings?) may be a great option to simplify the entire endpiece.

I have a handful of 92mm case fans from the close-out shelf of one of the local electronics store. The motors are rated 12v - 0.4a, so the output should be pretty decent without burning anything out for quite some time. Your turbine design should turn these babies very nicely. (I can blow on them and get them turning, so...woosh!) It's a very different machine, but I think it fits the "simple and readily available" criteria.

Am also curious to see how much power could be pulled out of your suggestions for beefing up the coils and such, though.
hi again, i just wanted to say that i would really like to get the response as soon as possible, cause i have to submit this project in college.

and i would upload the images of my project as soon as possible so that u r able understand the problems i am facing.

thank you.
hi there, i have to say that this project is a nice one but i am facing some problems such as
1- how many rounds of coil winding are used in this project.
2- i am not able to understand, on which part of the project is the CD with magnets attached is supported i.e. the CD with magnets is too heavy and needs a very good support. would appreciate if u upload pics of the supporting parts.
3- i would be very happy if u could provide me the link for the video of the making of this project.
4- i wasnt able to find the paper towel holder, therefore i made a wooden holder just like the paper holder.
5- a question- can we use LEDs to show the energy produced, and use a rechargeble battery for storing purpose.
Wesley6666 years ago
I have a bunch of hard drive magnets and I was wondering if they would work for the magnets. Also This project is alot like something I've built. I built a big fan and welded it to an alternator and that works wonders for generating power because alternators are so easy to turn. Another question is did you ever test the current and voltage of AC this produced before adding the DC converter/Bridge rectifier?
there's a wind turbine project I've seen that uses HDD magnets. they are polarized different then most magnets so they didn't work well at first. The project was made to work by cutting the magnets in half and attaching the halves back with one flipped to get the polarity to the wanted configuration.
cutting a magnet doesn't affect how it is magnetized. The end you didn't break is still either north or south, but the break still becomes the opposite for both halves. You can't break a magnet apart and one half is north and the other half is south. If you did somehow, you have broken laws of Physics. Magnetized objects always have to poles, they can never have a single pole. So breaking it in half just makes the same magnet but smaller.
right, but HDD magnets are polarized on the faces, not the ends. so a coil passing over a face won't pass through the strong points of north and south. cutting in half and flipping one side over makes a north and south on the same face, so then the coil would.
jshowell5 years ago
how about instead of a pringles can you use a squirrel cage like this one:
http://www.sciplus.com/recommend.cfm/recommendid/9940
and glue the magnets to the bottom and top of the cage. Gain electricity from both ends. Also there might be no need for a towel dispenser so airflow might be increased.
strmrnnr5 years ago
Couple of suggestions you have likely seen by now.

Levitation bearing magnets could likely be used and thinner coils with more wraps. I was throwing figures in an inductance calculator this Winter and found that the length of the coil really didn't make a difference most of the time except to use more wire, and make the coil more stable. If the coil is glued on a flat surface then stability is not a factor to worry about.

Also, other experiments I have seen use 4 magnets / 3 coils, but the wiring was a little different. That is what makes it tough for me as you guys all have new ideas and do this=ngs a little different. I guess when I finally get around to throwing one together mine while be different again.

Nice job!
sldhd75 years ago
what if you added more magnets than bobbins? it would help stop the "cogging".
ncblu5 years ago
cogging will definitely be a problem if you include any iron into the coil design. each magnet will have a "home" over each coil and the only wind that will break 12 cogged magnets free will likely trash the unit. your best bet is to offset the coils to the magnets. try using 9 coils instead, that way you likely wont ever end up with more than 2 magnets in a cogging location. if you use open air coils then your design will work fine because there is no iron to cog the magnets. coils can be wound easily this way. take 4 16d nails and put a 'z' bend in each one, hammer them in about 1/2 into a piece of wood on a circle drawn to the diameter of the coil. spin each nail so the head is facing outwards and start winding the coils, when done rotate the nails so the heads are now in the middle and you can slide the coil off in one piece and roughly the diameter you wanted. it's the simplest way to wind a good coil and this method is as old as the hills
Rudimus6 years ago
with step seven if you made a hole and used actual bearing you could achieve high rpm's without worry of the rotor popping off the holder.
Quazee6 years ago
try a pancake motor from an old CD/5.25/3.5 drive. I have played with a few.
Kralc7 years ago
in Step 15 it looks like the coils are mounted on a larger diameter than the magnets. If they are mounted the same distance from center you will induce more current per pass. Add jjjggbb's comments about iron for flux and you will have a big improvement. Silicon iron would be hard to find, so mild steel is a best bet. Did you count the number of turns per coil?? That could cause a phase imbalance if really different. Good Project!
mikejedw (author)  Kralc7 years ago
Hmm, might be an illusion in step 15--the center of the magnets passes over the center of the coils. I totally agree about the turns. I eyeballed it until they got out to a certain thickness, but in the next version, I'd like to do a much more accurate count. One method I've heard of is to attach a small strong magnet to a part of the drill used in the winding. Then electronically count the revolutions with a reed switch circuit every time that magnet passes back around. As for the flux, I'm still a little unsure. I mention in a comment below an effect I've heard referred to as "cogging" where the magnets get attracted to the ferrous parts of the stators, even briefly, causing the turbine to stutter as it passes through a revolution. Even this small amount of resistance might cause the turbine to blow less freely than it needs to generate a decent amount of juice. I guess you'd have to balance the speed you lose due to cogging with the increase in current from a steel core in the stators. Not sure what the best approach is, but I heartily encourage somebody to try it with the steel and report back on their results. Or even try it both ways with the same device and see which comes out on top.
attsen7 years ago
THANK U VERY MUCH FOR THAT INSIGHTFUL WORK.I'LL TRY IT.IF IT WORKS I PROMISE..I SHARE MY CASH WITH YOU.
jjjggbb7 years ago

Display the following in courier typefont for best results:

Think of the magnetic circuit as an electrical circuit. You want to maximize the flux through the bobbin coils.
      ________________     | magnet backing |     |    Material    |     |________________|     | S |magnets | N |     |_N_|        |_S_|       --air   gap--      ___          ___     | S |bobbins | N |     |_N_|________|_S_|     | bobbin backing |     |    Material    |     |________________|

We have the magnets as the equivalent of a voltage source starting out of the North pole. The voltage creates flux, the magnetic equivalent of current. the flux exits the north pole of the first magnet,passes through highly resistive (high reluctance in magnetics) air gap (nothing we can do about that but lower the air gap). Then the flux passes through the bobbins. If we wind the bobbins around iron, we get a lower reluctance than aluminum or, say, wood. Then the flux has to go through the base material. If it is iron, it has a lower reluctance. Then the flux passes through the other bobbin, then through the air gap again, then through the other magnet, then through the magnet backing material. All of these materials have a reluctance associated with them. The lower the total reluctance of the magnetic circuit, the more flux passes through the stator coils. Therefore, your motor or generator will work best with low reluctance backing materials. It is more complex than just this, but it amounts to the basics of completing the magnetic circuit.
mikejedw (author)  jjjggbb7 years ago
I totally agree with you on the magnet and bobbin backing material, and I've read comments from others that back this up. Using a steel paint can lid instead of a CD for the magnets and stators helps bump up the flux density and, in turn, the generated power. As for the bobbins themselves, though, we start to get a problem with what I've heard termed "cogging." That is, the magnets on the rotor attract to the bobbins, but not the spaces between the bobbins, so they resist moving away from them. It might not be a big deal in a high RPM generator, but since this is very much a low RPM set up, even small resistance can tank the efficiency of the turbine. Your mileage may vary, though, and I'd be interested in seeing the results from a steel bobbin setup.
jjjggbb7 years ago
I used to design motors, and I like this doohicky. Try using tin can lids of the same diameter instead of CD-roms. Make sure they are magnetic (ie the magnets stick to the lids). Use one under the coil bobbins as well. Istead of using a thread bobbin, find some solid piece of ferromagnetic material to wind your stator coils around. Nothing comes to mind immediately. Bolts (not stainless)? little bits of iron rod? Those small hex-shaped bits for putting screws in? Anything ferromagnetic. make sure the magnets stick to it. This should make for a better magnetic circuit. All that distnce across the back side of the CDs and the back side of the base and even through the bobbin coils counts as air gap for the magnetic fields. I think you will be suprised at the change in voltage for the same rotor speed. Motors use a lot of iron for this reason.