Stepping motor and its working principle

Update:05 Jan 2021

1. Stepping motor
Definition: stepping motor, also known as electric pulse motor, is an electromagnetic device that converts electric pulse signal into corresponding angular displacement or linear displacement.
2. Features: the speed can be adjusted in a wide range; the forward or reverse rotation of the motor can be controlled; there is no accumulated error, the structure is simple, the use and maintenance are convenient, and the manufacturing cost is low. But the efficiency is low and the heat is high. It is suitable for small and medium-sized machine tools and places with low speed accuracy requirements.

3. Classification:
(1) Stepping motor can be divided into fast stepping motor and power stepping motor according to its output torque;
(2) According to the number of excitation phases, it can be divided into three phases, four phases, five phases and six phases;
(3) According to its working principle, it can be divided into excitation type and reactive type.
4. Working principle of stepping motor
Stepper motor is a kind of actuator which converts electric pulse into angular displacement. When the stepper motor driver receives a pulse signal (from the controller), it drives the stepper motor to rotate a fixed angle (called the step angle) in the set direction, and its rotation is running step by step at a fixed angle. Take Figure 3-1 three-phase reactive stepping motor as an example to illustrate the working principle of stepping motor.

1. Single three beat control mode
When a group of windings are electrified, if a is electrified, the two teeth of rotor 1 and 3 are attracted by pole a; then phase A is powered off, and phase B is electrified, the magnetic field of pole a disappears, and pole B generates a magnetic field, which attracts the nearest 2 and 4 teeth, so that the rotor rotates 30 ° counterclockwise; when it is the turn of phase B, the rotor rotates 30 ° counterclockwise. In this way, press a → B → C → a → Turn on the power in turn, and the stepper motor rotates counterclockwise. If press a → C → B → a → Turn on the power in turn, and the stepping motor rotates clockwise. This is a single three beat control mode.
2. Double three beat control mode
Using the way of two-phase wheel current, that is, each time two-phase windings are electrified at the same time, and three times are converted into a cycle, which is called Double triple beat control.
3. Three phase six beat control mode
Six beats means that six times are converted into a cycle. In this control mode, if the power on sequence is a → ab → B → BC → C → Ca → a Then the stepping motor rotates counter clockwise.

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