This is a job with a mild difficulty for an engineering firm.
At the root, what I want built is a unipolar generator. The unipolar generator, dating back to Faraday, is quite a simple thing. Basically it's a magnet spinning together with a metallic disk. Current is taken between the rim and the axis.
This is a small item that can sit on a table. Motor is best to be 12V dc, compatible with car battery.
What I show in the attached file is a generator built by someone else, following the unipolar generator design. This is just to give you an idea about the size of the parts.
To have the best magnetic lines flow, the central part is going to be situated between two magnets, that are axially magnetized (this is important, as we need DC ; even if one magnet is diametrically magnetized, the resulting current is AC, which is not compatible with my design).
The modification
The central part is going to be the most complicated. Instead of having a metallic disk, what is going to be there will be a coil.
The coil will have to be wound on a core that is made of a material that resists magnetization while having a high magnetic permeability (TBD).
The core will be like a toroid with a central bridge. The shaft will go thru the central bridge and the core is to be affixed to it. The core will therefore move along with the magnets, just like the unipolar generator disk. It will not cross magnetic field lines like in a regular generator.
Bear in mind that this metallic core will be connected electrically to the axis, where one of the ends of the coil will also be connected.
In order to get the coil operational, the other end of the wire will have to be connected as well.
The coil will be insulated in a 3D printed coil casing, which is 99% designed. I attached a drawing featuring a half of the casing, as I imagined it. On the outside, it will feature a track, and inside this track there will be a brush ring. The other end of the wire will be connected to the brush ring. Due to the fact that the core is electrically linked to the axis, the coil casing bolts cannot be used to attach the brush ring into the track. A different method will have to be used.
Note that if there is a way to electrically insulate the core from the shaft, then bolts could be used to attach the outer brush ring to the coil casing, but bolts have to not cause bumps that would damage the brush.
Other requirements.
1. The parts have to have correlated sizes. The brush ring should not be outside the OD of the lateral magnets.
2. Magnets cannot be neodymium, as these would be electrically connected to shaft and may cause arcs later. In fact, no metallic parts should be anywhere near the outer brush ring.
2. The initial orientation of the magnetic field has to be N - S. North face of one of the magnets to face the South face of the other magnet. This would create complications due to attraction.
3. There has to be a way to easily dismantle the generator and put it all back without destroying collar threads during this.
I do not expect you to do anything electrical around the generator. If you want, you can do the winding of the coil and soldering the wire to the brush ring, otherwise I could do that part, but I have to be able to dismantle the generator. This is to experiment with different wires and different manners of winding the two half toroid coils sitting on the core.
I believe that from the moment of agreeing on this job, two months should be enough for build and delivery.
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