"Sylvia Else"


You can? What Phil said sounded perfectly reasonable to me. Now, it's true
that motors are indeed not my line of work, but the physics seemed right,
and fits with what the OP said.


** One can nit pick anything.

The OP needs to read the Wiki and my post and piece them together in his
head.

Chances are, the 400Hz wave is not phase shifted 120 degrees in each winding
so producing zero torque on that basis.

Also, at low speeds one needs lower drive voltages in order to to prevent
severe saturation of the iron rotor and the resulting large current flows.

Speed variation is a result of drive frequency alone.



..... Phil