Hi again folks!
Here's some update. I promised some test results for that car alternator seen above.
RPM Amps
------ ------
800 0,4
880 1,3
950 1,7
975 2,7
1000 3,7
1005 4,4
1015 4,9
1030 5,2
1035 5,8
1045 6,3
Volts were 14,5 in all cases.
This was measured on the output with the alternator powering field coil by itself. As can be seen, it would have suited my prop nicely around 7-10 m/s.
Unfortunately this test was the last thing that alternator would ever produce 'cause I continued with modifying it to PM alternator.
"Car alternator for dummies" :P
So I had few of those magnetron magnets laying around and figured that the easiest thing to do would be putting them in place of the original field coil. Well it wasn't easy neither was it wise. Now looking at it it's obvious that there's probably massive flux leakage directly between the "fingers" of the rotor and even without that they were far too weak. RIP car alternator.
At the moment the alternator chassis serving as set of bearings is still up on the tower for the mill to amuse everyone just freewheeling there. The furling system has proven to work although not known at what speed and the boat trailer hasn't dipped over, so that's still good.
As for now I'm planning to build a small axial flux alternator from hard disk magnets to suite my present prop and to continue with tweaking the tail and controls. Would you guys think it be wise to use the alternator chassis and fit the axial flux design inside or would the diameter be too small or something? I'm thinking of 8 poles and 2 coils per phase (3-phase) and aim for 14 volt cut-in. I would use two rotors and double magnets meaning I would cut hard disk magnets in half putting one half on top of other and then place 8 such sets on both rotors.
