mini dual rotor axial flux generator

[fungus]

Hi,

I've made this little generator today out of floppy drives and a few HD magnets. I've put all 6 coils in series from a floppy drive PCB. I kept the frame and single rotor from it and put a rotor from another floppy drive on the other side of the PCB and stuck 4 HD magnets on. It sort of works but the maximumi can get spinning it by hand is 0.4 volts(AC volts). Any ideas on how to get more volts?

heres some pics:




coils in series:



note: the circuit board was snapped halfway so I later could mount it easier.




Magnet rotor:



Two of the magnets were put the opposite way round because they were a different polarity to the other two.




blurry picture of plain magnet rotor



there isn't enough space between the rotor and the PCB to mount any more magnets.

[fungus]

I also forgot to add that it has 8.9 ohms resistance for all coils and also a little picture of it all put together:

I was getting 0.1v on my meter with one coil and 2 magnets. There is a slight cogging because of the extended magnets going over the screws.

[ghurd]

"all 6 coils in series"  doesn't go with 8 magnet poles.

You have a combination of single phase coils with 3 phase magnets.

Option #1. Single Phase. Break 3 HD magnets in half, space them right and it will work a lot better.

May have to switch coil ends.  Each should make the same voltage. If the total voltage is not 6x a single coil, one or more needs switched.

Option #2. 3 Phase. Get the coils reconnected for 3 phase star, and use 8 magnets.

G-

[ghurd]

Also, it looks like the steel mounting plate may go behind the coils?

That is going to cause eddy currents. You won't like Eddy and his currents.

G-

[fungus]

Actually, I think the mounting plate is aluminium.

[RP]

That's even worse as far as eddy currents go since aluminum's a better conductor than steel.  Can it be removed or replaced with a non conductor?

[fungus]

The mounting plate is behind both rotors and coils so will it still interfere?

[ghurd]

YES for the coils.  Say YES twice.  Place a quarter and a magnet on an aluminum cookie sheet and shake the cookie sheet around.  Then you can see what we mean. Bad.

And say YES for the rotor, but that is the GOOD kind of yes.  It helps a lot.  Sort of like the cookie sheet above, but the oposite.  It connects the magnetic field...

The coil connections or magnet count still need to be changed.

Something here may help.

http://www.fieldlines.com/story/2005/11/25/204242/17

G-