Consider a multi-stack, multiphase variable-reluctance stepping motor, such as that shown schematically in Figure, with 14 poles on each of the rotor and stator stacks and three stacks with one phase winding per stack. The motor is built such that the stator poles of each stack are aligned.
a. Calculate the angular displacement between the rotor stacks.
b. Determine the frequency of phase currents required to achieve a rotor speed of900r/min.
