I also wondered over that gap in the AIR403 magnet rotor.  I think there are maybe 12 smallish neo magnets?  I cant remember if the gap is a whole magnet width (The gap just wouldn't matter then?) but the stator is three phase (although there are different wire sizes on each phase - to allow for low RPM generation?) so you'd think that the poly-phase layout that iFred suggests wouldn't work so easily?  iFred's layout a phase per coil.

Of course the gap in the AIR403 is very handly for that metal band to be screwed down with.

Actually the AIR403 rotor/stator layout is very nice - but its just too small and I wonder if it is better to have the magnets on the outside like Hugh Piggots brake drum plans (seemingly scrapped now in this new age of radial designs).

I think the only reason SW put the space in the 403 was to have room for the screw that holds the band down to the amature. It dose make a cogging sound.

When I fist got the 403 I made the second mistake by mounting it to my metal shop. At low rpm it makes a growelling thats very anoing. Not to mention the blade noise.

How dose that poly phase thing work with N, S, N, S and the last north right next to the first N? Looks like there would be a bit of a lump or bump or a goofy wave form when this odd couple came around while the rest are normal nsns?

                        JK TAS Jerry

Airheads Page

I called the teck the third time and he told me to just take the little brain out. I did and it actully improved its over all preformance a little. I  would  say its preformance went from crap all the way up to suck. A small change but noticable.

Again this is just my personal observation of my own 403. Others may not share my thoughtrs.

                        JK TAS Jerry

Airheads Page