1st attempt - Magnet & coil testing project

[1memo1]

I have 2 approximate 20" steel discs (1/8" thick) that I have mounted on an axel, currently spaced with 1.75" gap between the discs (which is easy to expand if required.  On the inside surface of each disc, I have spaced 32  2"x1"x1/2" Neo's, about 1" apart.  I have only wound 2 coils so far, both were wound to create a 1"x2" hole, and are 1/2" thick, with the overall coil a little bigger than 2"x3".  One was made with 300 turns of 22 gauge wire, the other with 75 turns of 14 gauge.

I will be spinning the wheel at 150-200 RPM.  What is the optimum coil for these magnets, and how should the wheel be configured for 3 phase wiring?  Should I use 15 coils?  And what sort of power might be possible from something like this?

[willib]

With 32 poles you have 24 coils total.

3/4 *8/8 = 24/32..

thats 8 coils per phase..

[1memo1]

I can't fit 24, does that mean I need to space the magnets further apart and use less?  If I continue with this dimension of coil, I can fit a maximum of 16.  If I space the magnets further apart, I will no longer have 2 poles over  opposite sides of a single coil, so would I will need to adjust the coil dimension to make sure 2 poles are over a single coil?  Or is the best solution for these magnets to move everything in and use a smaller diameter disc to keep the space between 25 magnets around 1"?

[DanB]

You'll really want to get closer than 1.75" - a very small change in the airgap makes for a big change in flux.  Im afraid though your disks are not thick enough, those magnets would saturate the steel (youll get more flux with thicker disks) and I doubt they're strong enough not to warp if you get your airgap down to something more reasonable like.. .75".  You might get the magnet rotors right before you try to figure out the optimal coil...  fun stuff!

[kitno455]

memo- you probably want to build a 3 phase alternator. in order to do that, you either have to have 3 coils for every 4 mags, or you have to make a more complicated three layer stator.

you will have to space the mags and build the outer size of the coils to suit that goal.

allan

[willib]

No , you CAN fit 24 if you change the shape.

keep the width of the legs legs @ 1/2" .

also you should bring the magnets IN to 19.567" (perimeter dimention around the outside of the magnets)..

there will be 0.531" between magnets on the inside

http://www.otherpower.com/images/scimages/2965/coil_inside.GIF

this is a template for the inside of your coils..

the arc at the right side is a 19.567" arc..

enjoy..

[1memo1]

The 1.75 gap is between the discs, once I add a 1/2" magnet to each disc, and a 1/2" thick coil between the magnets, there is only 1/8" gap between the magnets and the coil on both sides.

How thick should the discs be for magnets like these?

And finally, that coil template, my coils currently do have a 1" wide center, which this template shows at the narrow end, so how could that fit more?  Perhaps I was off with the 1/2" coil legs, I will re-measure the current ones, and also try to make a coil like this.

For a coil as described, in this shape, 1/2" thick, what gauge wire should I use?

[willib]

what gage have you got?

your question of the rotor thickness is something i was questioning , 1/8 may be too thin, but again if that is all you have , then...

[1memo1]

I have #22 & #14  The 14 can take around 75 turns at this size I think.

[willib]

i would use the #14 ..

[Flux]

What do you want? what voltage, what cut in speed, is it battery charging, what power do you expect from your (VAWT?).

32 poles with those magnets at 140 rpm could make significant power, but do you have the power available to drive it.

Your details are so vague that nobody is going to help you. I understand HAWT but if it is VAWT you will have to feed me the details of power in.

1/8" thick is far too thin as DanB has already told you, magnetically you need 1/4" but even that is not too strong mechanically but if you don't have gyroscopic forces it may be ok. 3/8" would seem a better starting point.

My guess at this point is you will have to use several wires in hand unless it is a high voltage and if it is 12v it is going to be a pain to wind.

Flux