single or double rotor generator?

[amiklic1]

I am just starting to build double rotor generator, 2m diameter, 8 magnets per rotor ( 2"x1"x0.5"), 6 coils....

And I was thinking. Would it be more productive to put all 16 magnets to just one steel blade, and use 15 coils ( 5 coils per phase).

Also, if that's good, how to connect the coils? What diameter of the steel rotor is suggested??

many questions, and just one me.

[Waterfront]

2m diameter I take it is your prop??

If you put 16 magnets on a rotor, for 3 phase you'd only put 12 coils. (You said 15 coils / 5 coils per phase, that implies 3 phases...)

It's 8/6, 12/8, 16/12, 20/15... So if you want 5 coils per phase, with 15 coils total you'll need 20 poles...

For a 8/6 combo Hugh had a design for a 4' prop I believe... for a 16/12 combo the prop was 12' if I'm not mistaken, so, if your thinking about adding some more poles, you might want to think about a larger prop as well...

Just my 2 cents,

[dinges]

Productive or not is not the question; whether it's efficient is.

With a single rotor design, you need 'something' at the other side of your coils, like transformer iron (name?) to guide magnetic flux. Look at e.g. windstuffed, he used old microwave steel cases for this.

For me, this was the biggest hurdle in windgenerators; the Dans also built their first generators with a single rotor and magnetic material in or at the back of the coils; even tried magnetic sand, mixed with epoxy. I didn't see how I could make something like this. Until I noted the dual rotor designs. Easier to build (for me & with my gear), plus more efficient: twice the magnets, and more than twice the magnetic flux going through the coils.

Ask yourself why the Dans never went back to single rotor designs... (if I'm not mistaken; exception being the hampster generator ?)

That plus the fact that 16 magnets/15 coils won't give you three phase power. 15 coils & 20 magnets (per rotor) will, as the other poster explained. The famous 4:3 rule. BTW, you could also build 5 phase like Hugh P. does.

You decide.

Peter,

The Netherlands.

[amiklic1]

Thanks for the comments.

So, I guess I'll just stick to the proven High's plans for 500W machine, 2x12 mags/10 coils, and have nothing to loose.

I am looking or some larger machine, but right now I have nothing to power with that big. So' it's gonna wait for a while. And I'l probbably use Dan's design.

Merry Christmas to all!

[BigBreaker]

Definitely go dual.  You can use smaller, cheaper magnets and its not that much harder to make two rotor plates than one.  It's a no-brainer IMHO.

[dinges]

The 10 coils has me puzzled a bit, but it seems that Hugh uses this as a 5-phase design, judging from the other comments. If you simply stick to his plans you shouldn't go wrong.

I think I would build a 12/9 machine, but mainly because I have experience with those. The Dan designs use 12magnets/9 coils, not 10; this means a little less work winding coils, or you could keep one as spare or for testing purposes (I usually wind 2 extra coils, just in case anything goes wrong)

Good luck,

Peter,

The Netherlands.

[Waterfront]

«Just in case anything goes wrong»

Hope for the best,

Plan for the worse

It should be our motto, since it's applicable to pretty much every step of building something RE...

[elvin1949]

Don't forget Murphy's Law.

Anything that can go wrong will.

later

elvin