In FOC, maximum torque is achieved by keeping rotor and stator flux at 90 degree electrical angle. Why does electrical 90 degree separation produce maximum torque? [edit: removed the linked video]
It would at least make sense even if not true that, if 90 degree mechanical separation produces max torque, then I can visualize some cross product of fields resulting in max torque. But can't imagine a reason why 90 degree electrical separation of fields produces max torque. In case of 8 pole machine, 90 degree electrical field separation may correspond to 22.5 degrees mechanical separation.