Succesful mini wind turbine design
By gotwind2, Section Wind Posted on Mon Mar 09, 2009 at 08:04:45 PM MST
Air core radial design

Along similar lines to Wind stuff Eds great work with small radial axis alternators, here is my offering, connected to an off the shelf 3 bladed 12" diameter Radio control plane 'pusher prop' (mounted in reverse). I realise that this maybe not the best use of the neodymium magnet, but at such a small diameter i did not want to intoduce any magnetic steel anywhere near it (all fixtures are stainless) and obviously no cogging. I'm not quite sure what it would be classed as though, double pole single phase? It worked very well, spinning at over 1000 rpm easily and charged a 3 AAA NimH pack in around an hour (steady 16 mph wind), it also powered a cluster of 60 white LEDs, power approx 2 watts. I have put a page up with more detail and video on my site. http://www.gotwind.org/diy/12-inch-mini-turbine.htm If nothing else, it was good fun. Ben.

Succesful mini wind turbine design | 9 comments (9 topical)

Re: Succesful mini wind turbine design (3.00 / 0) (#1) by AbyssUnderground on Mon Mar 09, 2009 at 02:20:45 PM MST

Was it just the camera or are the LED's flickering in the video? http://www.repowered.co.uk - My Renewable Energy site. msn[at]m3ezw.co.uk - my msn if you want a chat.

Re: Succesful mini wind turbine design (3.00 / 0) (#2) by ibedonc on Mon Mar 09, 2009 at 02:32:52 PM MST

My wife is a science teacher , this would be a great project for the kids , she already did the biodiesel project :)

Re: Succesful mini wind turbine design (3.00 / 0) (#3) by wooferhound on Mon Mar 09, 2009 at 02:51:50 PM MST

Those coils look amazingly like Television Yoke Deflection coils I wonder if that magnet would work in those coils. W o o f -={(

Re: Succesful mini wind turbine design (3.00 / 0) (#4) by gotwind2 on Mon Mar 09, 2009 at 03:59:03 PM MST

Thanks guys for the feedback. Andy, yes the LEDs do flicker somewhat, I just used a simple bridge rectifier before the 60 LEDs - no capacitor or current control, electronics not my strong point. Any help in this area would be great? This idea has always been focused as an educational project ibedonc, personally I would have loved something like this aged 12 or even now aged 36 :) My only concern in the education area is the use of the very strong N42 cylinder magnet - health and safety nonsense in this day and age, don't get me started :) Ben. www.gotwind.org [ Parent ]

Re: Succesful mini wind turbine design (3.00 / 0) (#7) by ghurd on Tue Mar 10, 2009 at 07:37:02 AM MST

Place a fat cap on the bridge outputs. And a resistor in the pos wire after the cap. I doubt it will help much... with 60 LEDs! Each coil has its own bridge? Will get a bit better output using Schottkys. G- Ghurd.info [ Parent ]

Re: Succesful mini wind turbine design (3.00 / 0) (#5) by Flux on Mon Mar 09, 2009 at 04:30:34 PM MST

Yes the deflection coils would probably work as a 2 phase alternator. The ferrite yoke should drastically increase the output. Ben's design is more like the deflection coils of the era before ferrite that I remember from my TV repairing ventures as a kid. Flux [ Parent ]

Re: Succesful mini wind turbine design (3.00 / 0) (#6) by Stonebrain on Tue Mar 10, 2009 at 07:04:11 AM MST

hi ben, A pleasure to see something new on the raca front. I don't think it's a bad use of magnets.I even think that with an optimised 2 pole raca design(putting as much wire as close to the rotor as possible) you can catch more flux proportional to the amount of magnet then with most other designs. An iron'core',housing or iron wire onthe outside of the coils would make a substantial increase of voltage.This should be cilindrical(not square) to avoid cogging,eddycurrent losses are very low for such thing. What size of magnet did you use,how many turns in the coils? What non magnetic bearings are in it?Stainless ballbearing,bronze bushing or teflon bushing? For having a more accurate picture of the alt's performances,you should simply test the open volt output at different rpm's. I've been tinkering on a 2 pole raca design past winter. It's 3 phase though.Will be coming up with it when it's ready for the first test-windings cheers, stonebrain

Re: Succesful mini wind turbine design (3.00 / 0) (#8) by Todd a on Sun Mar 15, 2009 at 11:11:22 AM MST

So what size wire and how many windings do you use?  What size is that magnet?  How do you have the wires tied together?  I found the same 12" prop online for about $8 and a 16" for $12.  The only problem is their minimum shipping is $8.  I also found 2 1" cylinder magnets 1" long with a hole in the middle N42 and a 1 pound spool of AWG 18 magnet wire.  I was thinking of the end brackets in an X shape so you can have 4 coils of wire.  Then I could try it with and without an iron core in the middle of the coils pretty easily.  I could make it a 2 phase generator uning one small bridge rectifier.  I think if done right I might be able to get 5w or more...

Re: Succesful mini wind turbine design (3.00 / 0) (#9) by Catch66 on Tue Mar 17, 2009 at 06:39:02 PM MST

A very Cool project,well Done. Nice work. Chuck Renewable energy Its free

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