Question about axial flux gennies

[ruddycrazy]

Hiya Guy's and Gal's,

                     Well I've read the Dan's 10' wind genny project and searched and read a heap of old posts on the board and I'm slightly confused about the relationship of the front and back magnet plates. On reading Electric Ed's posts he shows pic's of when the north pole leaves the coil the south pole should be entering. Now on reading the Dan's project it states to put the north magnet on the back disk and the south magnet on the front disk opposite. As I'm doing alot of research I want to make sure I have everything right before I start my axial flux genny.

Now I'll probably get shot down in flames for this but the seeley motors I got have 20 57x42x10mm ferrites which do seem reasonably strong. I'm getting some more magnets so I can throw 12 on each magnet disk and as I have 24 volt array's on all my battery banks I reckon 70 turns of 14awg should be about right. I know the ferrites aren't up to neo standards but would I be wasting my time and efforts using them or would they put out a reasonable output? I'm not after Kw's and as this wil be my first axial flux genny I'm trying to keep the costs down as much as I can.

Cheers Bryan

[Flux]

Magnet discs attract, N on back disc lines up with S on front disc.

Ceramics will give you at best 1/3 of the flux of neos. You will need far more turns with associated higher resistance, expect 1/10 the output.

Using ceramics in place of neo is as your sign in name suggests.

Flux

[ruddycrazy]

Thanks for the quick reply Flux, RonB gave me a link to some Neo's so when my tax returns gets here I'll ordering the neo's. I sort of knew those ferrites are nothing better than big fridge magnets but one has to ask the question.

Cheers Bryan

[RP]

Your confusion about the magnet placement is a matter of context.

Assuming one magnet disk you want the north pole of a magnet over one coil leg while the next magnet (which will be a south pole) is over the opposite leg.  This will give you the effect of "as a north pole leaves the COIL, a south pole is entering".

Now the second disk with its magnets aligned over the first disk but with the opposite magnet poles dramatically increases the flux passing through the wires of the coil legs.  Think of the second disk as "sucking" the flux lines of the first disk so they stand straight out from the magnets.  This way the coils make a nice perpendicular slice through the flux lines which gives you the maximum generated power.

[etownlax]

Do you really want the a south and a north over each leg at the same time? Or do you want a south over the one leg and the north just back of the leg?

I don't know much about flux, etc but I'm tryin to learn.

-Randy

[etownlax]

I might have worded that funny... I meant to say...

"Do you really want a south over one leg and a north over the other leg at the same time? Or do you want a south over the one leg and the north just back of the other leg?"

[RP]

Ideally you want a north over the back of one leg and a south over the front of the same leg.  The other leg should have a south in back and a north in front.  All at the same time.

[etownlax]

ok;

thanks for the reply

-Randy