10 Magnets, 20 Coils, 2 Phase? Help!

[shockwind]

I am creating my first wind generator! I have 10 - 1" x 0.5" x 0.25" Neo's and it hopefully will be pretty similar to the small VAWT on WindStuffNow. It's a single rotor machine.

I want to use all 10 magnets in this design, so I have decided to go with a two phase slotted stator made from fibreglass with a steel disc backing. I have calculated that with these magnets and a 12 volt system, I will need 440 turns to reach 13.4 volts at 200rpm. So I have decided to make a system with 2 phases of 220 turns and then combine them in series to get the 12 volts. that will be 22 turns per coil, and 10 coils  per phase. Are my calculations correct? Am I missing anything? Would it be better for me to make 5 phases of 2 coils?

The magnets will be spaced on a 6" steel disc at 36 degrees apart. Giving me 10 poles.

This will be a single rotor machine, as I will be embedding a steel disc into a fibreglass ring and then drill and cut the slots for the coil windings.

Can you guys give me some suggestions or feedback on how you think this will work. What size wire should I use? How much power can I expect? 20 watts? Would it be better for me to buy 10 more magnets and make a dual rotor machine instead of the steel disc behind the coils?

Here is a drawing of the stator that I did.... hopefully it helps... any feedback is appreciated.

Thank You

[Flux]

If I understand correctly you are using a stationary steel disc as a backing to a single rotor. This will not work, either you will have to use a laminated backing disc made from a coil of magnetic strip or you will have to rotate the solid disc with the magnet rotor. With a stationary solid disc most of your output will go into eddy current losses.

If you want the advantage of a 2 phase machine, you must wind each phase for the required voltage and rectify them separately.

What you propose is single phase with all the problems that go with it and doubling your turns by adding the coils in series will only give 1.4 times the voltage.

A 10 pole 5 phase winding will be a nightmare, I think you are confusing it with Hugh's 12 pole 10 coil 5 phase winding.

Flux

[shockwind]

Hey Flux, thanks for your reply.

I haven't seen Hugh's 12 pole 10 coil design (My book hasn't arrived yet, but it's on the way)

I understand how I will not reach 12 volts with this now, thanks for pointing it out.

So I guess if I have to make a disc that rotates behind it, I might as well put some magnets on there to boot, making a dual rotor machine. I guess that is what I will be building now.

What wire size do you recommend for a machine this size (6 inches)?

[Flux]

I agree about adding the extra magnets, one of the main problems with single rotor alternators is finding suitable lamination material at a sensible price.

You will have to settle the number of turns first, then you can decide on the largest wire size that you can squeeze in.

Flux

[shockwind]

Great, thanks for your help.