Motor coil oscillation

Anyone have an idea why there would be this oscillation (when measuring the coils on a motor while externally driving it)? Would a weak coil cause this? Hard ard to test the coils independantly since their inductance seems to shift with shaft position. The latter I assume is normal.

Build the rotor / magnets and then measure.
Greetings Frank

What do you mean by this oscillation? I am not a expert but this looks about correct

There seems to be a slow magnitude oscillation that seems to be happening at a slower (in this case by a multiple of around 18) than the actual phase pulses. Strangely working it’s way through the phases.