A rotary stepping motor is deﬁned as a singly-excited motor converting electric pulses into discrete angular displacements. It has salient poles both on the stator and rotor but only one polyphase winding. Normally, the stator carries the winding which is sometimes called a control winding . The input signal (pulse) is converted directly into a requested shaft position, without any rotor position sensors or feedback. Stepping motors are highly reliable and low-cost electrical machines compatible with modern digital equipment.