I had some insomnia this night, so I thought a little engine. Unless my insomnia comes from the fact that I just thought about this engine, I do not know too much
The basic principle is simple: a magnet attracts a ferrite core, except when the latter is "magnetized" by the passage of current in the coil around the ferrite core.
So by mounting the magnets on the rotor, and with tori on the stator, and magnetizing at the right moment tori so that the magnets are no longer attracted, the rotor turns and gaining speed because there is an imbalance, when the magnet approaches the torus it is attracted, but when it moves away it is no longer.
Instinctively, I will say that the tori must be magnetized until the magnets have traveled half the distance to the next torus. Otherwise the magnet is again attracted by the previous torus, which should lose a little torque to the engine.
However, on the various videos, the coils seem to magnetize during 1 / 3 time, even a little less, which makes that the torus is demagnetized while the magnet has only one third of the way to the next torus , curious.
In any case, one thing is certain, the maximum torque of this motor is only linked to the "force of attraction" between the magnets and the toroids.
So the torque is maximum when the torus has no influence on the magnet in the phase of removal.
It can therefore be said that if the current in the toroids is independent of the resisting torque applied to the motor axis (demonstrated in the JLN tests), on the other hand
the maximum torque of the engine is well dependent on the current in the coil in the magnetization phase: if the current is not strong enough, the torus must still attract a little magnet, the imbalance between the approach / removal phase is not maximum, and so the torque is not maximal either.
On replicas, including that of Naudin, we see that the engine reaches a moment a max speed. This one corresponds in fact to the balance between the max torque and the resistant torque due to the friction of the bearings and the air.
My intuition is that despite the confusing appearance of the engine, it can never be superunit, because you can never use more mechanical power on the rotor than it takes electrical energy to magnetize tori. To have more mechanical power it would take more torque, so a greater attraction between toroids and magnets (magnets more powerful, etc ...), but suddenly more current to magnetize tori.