The Wind is Free!

You are right. My mistake. (You're pretty sharp )
It's 115 rpm @ 4m/s and 229 rpm @ 8m/s

Hmm, . . .that's going to make quite a difference. At half the rpm, I will only get half the voltage and that's not good enough. (Wonder what else is wrong )

. . .How do you get a rpm of 458 at 8m/s? I get 225rpm. Have you perchance confused radius and diameter in you calculation of circumference? :thumbdown: I'll check it out now. And do you know the generator efficiency? I.e. mechanical ...

Ok, you are at sea level.

How do you get a rpm of 458 at 8m/s? I get half of that. Have you perchance confused radius and diameter in you calculation of circumference?

And do you know the generator efficiency? I.e. mechanical to electrical conversion (or can you estimate?).

I'm about 300m above sealevel. I'm reposting: This is my design draft for final discussion. It’s based on the results my computations and windgat’s recommendations. ⋅ I’ve (finally) accepted the rectangular magnets, ⋅ appreciably increased the number of turns per coil, ⋅&nbs...

What is your altitude (above sea level)?

Problems . . . problems

This is my design draft for final discussion. It’s based on the results my computations and windgat’s recommendations. ? I’ve (finally) accepted the rectangular magnets, appreciably increased the number of turns per coil, increased the size of the rotor and stator to speed-up the magnets, and ? gone...

OK, I think I've got this thing taped (finally :wink: ) Rectangular magnets give better responses. http://forums.tfhmagazine.com/images/smilies/waahooo.gif This is what I've been trying to work out. Two magents: one rectangular and one circular, both with the same strength and area s...

So I suppose the issue is which shape produces the higher average 'response'? About dropping to zero... if there are three phases then there is always one phases near its peak.

... out the response of a coil moved in front of both magnets to see the difference. The discs produce a (large) leading voltage spike followed by a much lower tail, whereas the rectangles produce smoother, but lower responses that drop to zero the moment the magnet is withing the circumference of ...

Seems bit like overkill. Maybe more efficient coil shapes plus fitting in more turns would allow much smaller magnets to give the same effect? Remember that even without too much copper packed in and 8cm^3 per magnet (N35) I got over 500W (see above), so with 13.8cm^3 (46x30x10) ...

I looked-up the prices of the magents I fancy: discs 25 by 12.5 by 20 thick. Best price: $20 each, and I need 24 of them

Why so much for magnets? Maybe I can arrange better...

Let me explain what I’m contemplating: I’ve been thinking of using a wind turbine to power a geyser, by connecting it directly to the heating element. . . . Not given up on this idea, but . . . - having discussed this with the XYL - I can't justify the expense of ...

... is a factor or not... And 0.8mm is okay with 8amps? BTW can you tell me how much current you think is safe to put through the 1mm wire I use? It would be easier to visualise ...

Aha, I understand, tx. And now I think (finally) my left brain has caught up with my intuition... When the magnet is aligned as on the left, as it 'leaves' one of the coils legs it 'arrives' perfectly at the other. But look on the right - when it 'arrives' at the first leg the shape doesn't match. I...

BTW: I'v got another design. This time I'm using rectangulat N42 magnets.

Tell me what you think.

First coil, but . . .
that's because the second coil doesn't cover the full flux change. It's hasn't enough height compared to the magnet.

Is it not the vector of the wire in the direction of 90 degrees to the movement of the flux? I may be using the wrong words, please correct me if I am...

Maybe a picture will help explain what I mean. Consider the following layout. Which coil will be able to deliver more power(/voltage/current)?

... If you are sure that shape is unimportant, try imagining winding the coils in the shape of clover leaves... I didn't mean that. I meant circles or rectangles. It's the area that counts. The bigger the winding, the greater the fluxchange, the higher the induced voltage. 532 Watts :o That's impre...

In a storm the other day I had the 20x50x8mm magnets up with 1m blades. I saw it go to over 19amps, but only caught 17amps with the camera - here's a frame grab from the video:
With the dump load kicking in at 28V, 19A means 532 watts!

Hmmmm . . not sure. The induction is voltage, NOT current, which depends on the area of induction covered by the coil (independent of shape) :P Whatever! In my setup the max voltage is in effect clamped to 28V, hence I think of current. Point is the same... Independent of shape?! Can't be... the ma...

... is not to let them induce opposing fields into adjacent coils. It's much easier to avoid with rectangular magnets. Your tip speed ratio is 3.7? How many blades? That seems small for a 3 blader... Now I thought I understood you. My mistake. ...

... turns of 0.8 seems like very small coils - I think you could easily fit more copper in there. I think you're right. Your tip speed ratio is 3.7? How many blades? That seems small for a 3 blader... Didn't consider this. There's a number of other things I didn't consider. I think this is a cr*p ...

... to wedge shaped? 34 turns of 0.8 seems like very small coils - I think you could easily fit more copper in there. Your tip speed ratio is 3.7? How many blades? That seems small for a 3 blader...