6" rotor axial flux 2 blade success

[gotwind2]

Since receiving Dinges's first attempts at making an axial flux alternator, I was undecided how best to use it.

Dinges has gone on to bigger and better things now as some will know.

The received alternator was a 6" diameter dual rotor design, with great bearings and zero cogging (obviously), the original build detailed here.

http://www.fieldlines.com/story/2005/11/13/32021/791

At first I thought of a vawt design, but with a 12v battery cut in speed of 450 rpm that was too high.

I decided on a Hawt design with a simple 2 blade 32" diameter pvc prop.

I was very surprised at how easily it span. I am used to the heavily cogging sturmey Archer dynohub and the ametek 30v DC motor, the later doesn't really cog but there is  mechanical resistance.

I tested it on a small stand 3 foot from the ground in my very turbulent garden and it easily lit a 12v - 5w Luxeon LED in a moderate wind, I will get it raised to 20 foot and hook it up to a battery soon to see what it can really do.

This just proves the efficiency of the axial flux air core design even on a small scale in a very turbulent area.

Video here.

http://www.youtube.com/watch?v=i5Uv0ZLIBQQ

Thank you to Dinges for the alternator.

Ben.

[tecker]

The stator must be too thick .

[tecker]

The metal work is nice Cool design.

[Tritium]

Ben,

You said "12v - 5w Luxeon LED"  What is this part? Vf on most 5W luxeons is a little over 6 to just under 7 vdc. By the way cool mill.

Thurmond

[dinges]

Hi Ben,

Looks very nice!

Glad that genny got put to use, it had been gathering dust in my shop for the past few years. Watching it spin was very pleasant. Was sitting with a stupid grin on my face as I was watching Youtube.

Tecker, yes, the generator is not perfect. The airgap is too large and the holes inside the coils are too small for the size of magnets. What can I say, I've learned a thing or two on generator design thanks to this board. I told Ben that, if he built a new stator, output would be improved quite a bit. It's up to him now  The good thing though is that, despite its shortcomings, this thing still puts out quite a bit of energy for its size. But, it could have been more, had I known then what I know now.

Peter.

[wooferhound]

The tail boom looks to short to keep it properly pointed into the wind

it looked like that on the video too

[gotwind2]

Thurmond.

The Luxeon leds are available in 5 and 12v versions, imported from China, not cheap, £20 ($40) each. Equivalent to a 20w Halogen apparently.

Will run from AC or DC - see label below.

Ben.

[Flux]

Nice work.

Yes you are right about the starting, The Sturmey Archer thing is about the ultimate cogging device with totally miserable output. Those dc motors do have a lot of drag, usually half brush friction and the rest iron loss.

For your low wind area the ironless machine is the way to go. Not really sure if you have a good match to those blades but you are on the right track.

For a machine with no offset I am sure your tail is big enough, it will point all over the place in a turbulent environment, a longer tail may make it look happier but it will not make much difference to the output.

Flux

[Tritium]

Ah,  now I see it is a driver/led package. I have built something similar for about $30 US. Makes sense now. Thanks Ben.

Thurmond

[richhagen]

Ben, that looks good so far, I am not sure of your power out at this point, obviously you were within the voltage parameters of the light though.  It will be interesting to see what current you get out into a battery with that stator, and compare it with a new thinner stator, a bit less of an air gap and/or thicker wire.  Rich

[prototype]

Hi,

I want to buy a axial flux alternator, something like this

http://www.gotwind.org/diy/Axial_Flux_Alternator.htm

but where to buy? any idea??

I need a alternator for my VAWT prototype, 80cm x 45cm width

The alternator need to be low in starting torque and friction.

Thank you very much!!