What is the working principle of a stepper motor?

A stepper motor is an electric motor that converts electrical pulse signals into corresponding angular or linear displacement. Its core function is to achieve precise positioning of rotational angles or linear movement distances by accurately controlling the number and frequency of input pulses, while also possessing high reliability under open-loop control.

A stepper motor generates a rotating magnetic field through the alternating energization of its stator windings, driving the rotor to rotate gradually at a fixed step angle. Each input electrical pulse causes the motor to rotate one step angle (such as the common 1.8° or 0.9°). Its position and speed are entirely determined by the number and frequency of pulses, achieving open-loop control without a feedback system. This characteristic makes it irreplaceable in scenarios requiring precise positioning, such as 3D printer nozzle movement and CNC machine tool tool feed, achieving positioning accuracy up to ±0.01mm.