The speed of the stepping motor depends on the pulse frequency, the number of rotor teeth and the number of beats. Its angular velocity is proportional to the pulse frequency and synchronized with the pulse in time. Therefore, when the number of rotor teeth and the number of running beats are fixed, the required speed can be obtained by controlling the pulse frequency. Since the stepper motor is started with the help of its synchronous torque, the starting frequency is not high in order to avoid losing step. Especially with the increase of power, the rotor diameter increases and the inertia increases. The starting frequency and the maximum operating frequency may differ by more than ten times.

There are many structural forms and classification methods of stepping motors, which are generally divided into three types according to excitation mode: reluctance type, permanent magnet type and mixed magnet type; According to the number of phases, it can be divided into single-phase, two-phase, three-phase and multi-equivalent forms. The starting frequency characteristic of the stepping motor makes it impossible to reach the operating frequency directly when the stepping motor starts, but there should be a starting process, that is, gradually increasing the speed from a low speed to the operating speed.