12 pole single rotor vs 6 pole dual.

[kihon]

While waiting for more copper to build another stator, Im thinking about makeing another set of rotors.

My current design uses 24 small bar magnets, with relatively low strength. I also have 12 25mm Diameter 20mm thick magnets, which Im thinking of using in another set of rotors.

The 12 magnets are a little bit more expensive than the 24 smaller ones, but Im hoping their greater strength will lead to a better gen.

looking at this design

http://www.otherpower.com/woodax.html

They seem to get a decent amount of power with similar magnets,using a single phase design.

I was trying to work out if this would be better than using a dual rotor single phase design with 6 magnets either side.

Any thoughts?

As always, thanks in advance.

Kihon.

[KilroyOdin]

Hi, I think you would do better using 12 mags and a three phase coil configuration. The design you are looking at has some good ideas. When you make your coils the center hole of the coil should be a little larger then the size of your magnets. When the magnet is over both sides of the coil it produces a null affect. If you configure the metal plate that directs  the lines of force through the coils to rotate you will not have a problem with eddy currents slowing down your rotation speed.  Best of luck with your project and hope to see some photos.  

Live in the present and plan for the future.  

[kihon]

Just added some images of how I imagine the magnets and coils to be..

First the 12 pole 3 phase design, dual rotor, but magnets on one rotor only.

And the second design, 6 pole dual rotor, magnets on both sides, but single phase design.

I dont want to glue the magnets on until I am sure which design to go for. I guess the best thing to do is to place the magnets for the 12 pole design and try out a coil or two first (I suspect that the 6 pole design the magnets will fly across the gap if I dont glue them down.)

[electrondady1]

in the first image the magnets are too close together.

 in the second image they are too far apart.

create an overlay of the coil  configuration

and rotate that over the magnet one .

you will see what needs to be changed.

[Simen]

How about making a 12pole, 3-phase dual rotor, but no magnets on the second rotor? That way you'll have a returnpath for the flux, and the option to add magnets on the second disk later...

[KilroyOdin]

 A trapezoid coil shape will increase the  perpendicular surface area of the coil to the magnetic line of force resulting in an increased output.