My newest small genny project I'm trying to build.
24pole 18 coils, #23 wire and 1/2"x1/8" disk Neos N42.
The wire I got is used 4.7lb coils from machinery. I have about 5 coils or about 22lbs, changing wire size is not an option.
I have no idea what it was for, but a solid 1 strand coil wrapped in cloth and resin coated. It measures 0.023 with calipers after cleaning an end. Except for the turns against the clothe with a little resin stuck to it this is like new wire right off a roll.
I have mounted the little Neo disks to the 6" steel disks, I used a bicycle axle for the hub. The plan is put the blades on one side and the rotors on the other side on the axle and mount the hub solid.
I had extra length on one end and a bit short on the other end, so I cut more threads. I think that was a 5/16 24 die.
The first rotor I tapped the center hole, so the axle nut for the bearing is in place and I screwed on the first rotor really tight. This makes like a jam nut so they lock each other, then I put on a second nut tight against the rotor plate making another jam nut and also part of the spacer for the air gap.
I drilled and tapped 4 holes for jacking bolts in the first rotor to lower on the second rotor, backwards from the way it's normally done though. I have 4 holes in the front rotor I will tap those later also. I think my tap wore down that fast since the last hole I tapped is hard to turn the screw but the first 3 are perfect.
At this time the airgap is about .36" which is kinda wide for 1/8" thick Neos. For now the spacers are 2 nuts and a washer but once I decide the final airgap I will make a wide aluminum spacer which will support the rotors and hold them apart, the rotors are only 1/8" thick. Even with the wide airgap and thin Neos I was surpised at the pulling force. With only 1 center hole the front rotor spun around to self align with the rear plate. My front and rear holes were not lined up and I was going to put a pin though 2 holes, I could not turn the rotors by hand, the attraction of the magnets keep them where they are! Not a problem but I did not expect that much pull that far apart really.
Testing was a pain today and poorly done. I held 1 coil by hand, 40 turns 1/4" thick, between the rotors and ran them with a cordless drill, axle clamped in a vise. I checked RPMs with a laser tach.
The following open volt results for that one coil.
Rpm 140= .1V
RPM 266= .2v
Rpm 332= .3V
Rpm 441= .5V
Rpm 667= 1.0V
Rpm 762= 1.1V
All AC volts
That was rough test just to see if I would get any volts at all. Holding the coil by hand trying not to bounce off magnets was not easy!
Here are a few options I can do. The coil can be wider yet, I could do 2 inhand, or allot more turns. The airgap is too wide at 0.36" and I can close it some.
The coil could have more turns and also be thinner but not able to to do 2 in hand that way.
There will be 18 coils total. 3 phase there will be 6 coils in phase at a time. I am thinking 3 coils per phase and 2 phases parralel. My thought on this is that 2 phases parralel would be basically same as double the wires in hand per coil, but spread out for more pole changes. Each coil will see 24 poles per revolution. Heat will be spread out also.
Sugestions welcome. Pics to follow I hope!
This will be for a 12V system if it works. A small unit for on a friends camper.