Steve,
Your right. The rules are unbendable. The laws of the universe are black and white..... whats different is how we use things.
The axial flux alternator is the absolute pits when it comes to using the flux sensibly. It is one compromise after another. But it is easy to build, and we can throw heaps of magnet at it. With neo, that is all it takes to make it work very very well.
With ferrite, it becomes obvious how bad the design is, as without Chris's gearbox, it is next to useless. With his 130cubic inches of ferrite, you can easily make a very very powerful alternator at direct drive speeds. The AWP uses less than 90 cubic inches of ferrite, and makes an easy 2kw direct drive..... but it is not axial flux. It uses the flux more wisely, and as such is very very much better at generating power at very much lower rpm..... downside is it is not possible to build at home unless you can find stampings..... so thats out.
Knowing how bad axials use flux, and knowing all flux lines leave and return..... well if we aren't using them then they are leaking all over the place. If we used half of the flux we would be going very well. so losing flux at the back edge will mean nothing in the scheme of things.
Another reason why shorting flux on the outside does nothing bad for this design can be seen by just looking at the geometry of the coils and the placement of the mags. It would appear that the outside edges of the mags are never going to contribute any emf, as the coils windings under them are running not perpendicular to any field, but parallel.... so if you short the field, they won't know anyway... ie the electrons in the wire are being displaced from side to side not along the wire, and will contribute no emf to the output. So no surprise that he could not measure any meaningful difference............but the tabs hold the mags on... and thats a good thing, and they are only shorting non-useful flux... thats a don't care thing...... and it still works... and thats a great thing.
.................oztules