Question

If a hybrid stepper motor has a rotor pitch of 36º and a step angle of 9º, the number of its phases must be

(a) 4

(b) 2

(c) 3

(d) 6

The question was posed to me in an interview.

My enquiry is from Stepper Motors in section Control System and Components of Control Systems

Answer 1

The correct answer is (a) 4

For explanation I would say: Step angle is defined as =(Ns-Nr)/(Ns+Nr)*360.