The coil setup as shown here appears to work very well off rotor. It is 4 individual sections of 3 coils cut from a Fisher & Paykel Smartdrive washing machine motor. The copper wire is removed from the outer 2 legs, and one of these wires is wound around the center coil in the same direction and connected in series. I have tried with the outer legs removed, but the coils will not work. The legs are the path for the magnetic flux.
Fitted to the front of the coils are 4 ferrite bars 40 x 12 x 5mm. These seem to smooth out the electromagnetic field and may even increase the airgap distance. All 4 coils are then connected in series. It becomes one large electromagnet with all polarities the same.
The four coils connected in this way are the best and strongest arrangement I have been able to make. However the motor requires that two of these "quad coils" are connected in series, and the coils are then not as effective. What I have done is to connect two coils of each quad coil through two parallel 3 phase bridges