Any small wind generator plans??

[amiklic1]

I need some plans for 5-6 blades really small wind generator, with power from 60 to max. 100w.

I would mount it on the boat, so small diameter is something I need.

Also, it should be intended for 12V.

Or, any comments how to arrange some genny, coils , magnets etc, to be as small as possible.

Rotor diameter should be no more than 60 cm. Yes, really small one, I know.

[tecker]

 Motor conversion  

[amiklic1]

Yes, I've been thinking about that, but I'd rather build some axial, with neos.

Also, is there any PM motor that can be used here? Some servo or something like it?

[richhagen]

I've been playing with stepper motors as of late.  One of the ones I have is a Pacific Scientific 116 Inch Ounce stepper, Nema 23 format, at 24 volts.  It would make for a relatively simple setup somewhere around your power range.  Rich Hagen

[johnlm]

A comment about the size:  Sounds like you are anticipating pretty stong winds if you are expecting 75 to 100 Watts from a 60 CM max blade diameter.

John

[Ungrounded Lightning Rod]

I wonder if an axial-flux or a motor conversion would screw up the compas more?

Axials have the advantage that you can embed virtually all the metal parts in epoxy, epoxy-paint, or weather-resistant sealed electrical connections.  That's dandy for salt-water environments.  But conversion of a corrosive-envrionment motor might be even better.  You could seal that puppy back up and paint over the screws.

I'd use stainless-steel-against-delrin for the yaw and furling bearings.  And I'd take the whole mill down and away from the sea, clean off the salt, and get it bone-dry before opening it for any maintainence.

[amiklic1]

I wrote 60, to max 100 watts. Think, if Hugh's plans of 4-foot engine = 125 watts, then I could expect some 60 watts in normal winds. And maybe even not. I was thinking of 60 watts at 10 m/s, and would be happy if that could be done. I think I'll just try some experimenting with 6 coils/ 8 magnets system , and see what can I get. Hope that would work. If not, some more experimenting , and so on.....

[amiklic1]

Yes, stainless, of course. Even on my first 4-foot turbine ( Piggot's design) I am using stainles on all metal parts. The only thing that is not stainless is steel plate of magnet rotor. That's because stainless is allmost not attracted by neos.

When you're thinking of corrosive environment motor, can you suggest something, maybe some web page? Because I really don't know where to look for that. That is the reason I think that building my own genny is the right choice.

And about the compass, it does not screws it, if it is mounted at some distance from it. Think that 3-4 m is good distance for that, in the case of small generator.

[wdyasq]

A 60cm rotor is less than 1/4 the area of a 4' daimeter rotor.

Ron

[Jerry]

I was just looking through wind wind test notes. My GM car alt conversion is doing 95 watts at 15 mph with my 3 blade 49" prop. A GE ECM would work well also.

                     JK TAS Jerry

[amiklic1]

Would I experience the same with 6 blades and half rotor area, as with three blades and the same rotor area? The blade area of the 6 blades should be the same as of 3 blades, in that case???

Idea:

If I put half size blades, let's say about 30 cm, it is allmost one quarter of an 125cm rotor area. If I give just some more length to get something more than 1/4 area, and than put 6 blades, to catch more wind. Would it work?

[johnlm]

>Would I experience the same with 6 blades and half rotor area, as with three blades >and the same rotor area? The blade area of the 6 blades should be the same as of 3 >blades, in that case???

Answer: NO

>Idea:

>If I put half size blades, let's say about 30 cm, it is allmost one quarter of an >125cm rotor area. If I give just some more length to get something more than 1/4 >area, and than put 6 blades, to catch more wind. Would it work?

Answer: NO, it would run but would not give you the power you think.  Area = Pi X Radius^2 ; therefore the area for a 125 cm prop is 1.22 square meters, the area for a 30 cm prop is 0.07 square meters; 17.25 times smaller than a 125 cm area.  

The answers are regarding your train of thought that if you add more blades to the same size prop you get more power.  It doesnt work that way, in fact as you start adding a bunch of blades you start getting less power.

Out of a 60 CM (~2 ft ) prop you will get roughly the following.

10. mph   5 watts
    
15. mph   16 watts
    
20. mph   38 watts
    
25. mph   75 watts
    
30. mph   130 Watts
    
    

as you can see your not going to get near your 75 to 100 W in low to moderate winds.

The way to calculate this has been posted maybe 10 times in the last month.  Se a post by picmacmillian from a few days ago trying to explain this concept.

Good luck.

John

[amiklic1]

OK, than. But it would be good to have that output, as I am looking hat output at 10m/s wind speed. And that is around 2,5 mph.

I also need an advice how to arange the generator. Can I use Hugh's plans for that???

It seems that generatr area is going to cover very large part of the blades area, and that is something I do not want.

So, the suggest is to take 3 blades, and on 10 m/s I coud get about 60 W. I'll try.

[Jerry]

Most PM motors used here are about 4" in diameter. This is acceptable area behind your small blades.

                     JK TAS Jerry