The lathe has arrived, but the three phase motor renders is pretty useless at the moment. I've decided to play a little
more with the current motor. Firstly I modelled it in FEMM to see what my rather arbitrary design has resulted in.
All things considered, it could have been much worse. Average flux density in the gap is around 0.32T. With FEMM you can
also create a graph of the flux density in the gap.
This shows a good 3.5-4mm of linear flux density in the gap. The next step is to use a better former. I had one cut out of
aluminium to fit the gap perfectly but eventually learned that this creates a shorted turn, and requires a cut down one side
to prevent this.