I always added an extra pair of magnets on both sides of the magnet pair I was looking at. With 3 complete magnetic circuits I was fairly sure the middle one was close enough.
Good stuff SparWeb, - my interest lies in "how about the steel closing it off (in single magnet cross section view) ?"
Hmmm... trying to explain this in text... Again, think 3D. Drawn in our 'side views' with the alternating magnets, it would either blanket everything or show as a closed end again. Interested in single magnet cross section (static) view, since moving the rotors in the side view with the perimeter disc steel poses a problem in that they are in a straight line and closing the end smashes into that end. I reality, the path exists - but can't really be modelled in the side view - aside from closing that right / left side off. Drawn as one magnet at a time, there looks to be an increase.
We can ignore the wood rotor and reversed magnet examples as well...
They are diary entries for interest / a laugh.
My question comes back to this...
Current...
vs. this...
As I have mentioned to RP, and again not to sound glib,- have you tried this and found no increase in output, or in fact a reduction in output? It might be that ~'all' of the (useful) flux is already channeled in the other (angular) plane/direction. I am OK with that, just looking to hear that / see that someone has thought of this, tried this, recorded this, prior to building it and charting output vs. my current build. Afterall, the reason my rotors are steel and not plastic, rubber, wood, is that someone (Hugh) gave me that advice.
It may come down to building another stator for a few reasons - that in the medium term anyhow - which is OK too.
Since all of my connections are outbound from stator, the reality is that I'd have to -
1) Disassemble and build the ring on the inside, as close to the magnets as possible and without coil intereference.
2) Re-wire, pour and mount stator so that the connections run inbound toward shaft.
#1 would be more scientific, since I would have results of adding the perimeter steel vs current.
I don't mind #2) either though, since I could then loose the 1/8" plexiglass on each side of the stator.
Will model that later this afternoon. I am almost certain there will be a B gain there.
There would also be a gain in flywheel effect with the additional steel perimeter.