Stepper motor is an open-loop control element stepper motor that converts electrical pulse signals into angular displacement or linear displacement. By controlling the sequence, frequency and quantity of electrical pulses applied to the motor coil, the steering, Control of speed and rotation angle. With linear motion actuator or gear box device, more complex and precise linear motion control requirements can be achieved. Stepping motors are generally composed of front and rear covers, bearings, central shafts, rotor cores, stator cores, stator components, corrugated washers, screws, etc. Stepping motors are also called steppers. The conversion into mechanical energy is driven by coils wound around the slots of the motor's stator. Typically, a piece of wire wound in a loop is called a solenoid, while in a motor, the wire wound around the slots of the stator is called a winding, coil, or phase.

1. Basic structure

2. Working principle

According to the external control pulse and direction signal, the stepper motor driver controls the winding of the stepper motor to energize forward or reverse in a certain sequence through its internal logic circuit, so that the motor rotates forward/reversely, or locks.

When there are control windings on the six poles of the stator, two opposite poles form a phase.

Note: The concept of "phase" in three-phase alternating current is different here. The stepper is connected to the DC pulse, which mainly refers to the difference in the number of connection groups of the line.

3. Working process

1) The A phase is energized to align the rotors 1 and 3 teeth, and the magnetic flux in the A direction forms a closed loop through the rotor. If there is a certain angle between the rotor and the axis of the magnetic field, under the action of the magnetic field, the rotor is magnetized, attracting the rotor, making the position of the rotor try to minimize the reluctance of the energized phase magnetic circuit, so that the teeth of the rotor and the stator are aligned to stop rotating.

Phase A is energized to align rotors 1 and 3 teeth

A phase is energized

Phase A is energized to align rotors 1 and 3 teeth

B-phase energized C-phase energized

This working method is called three-phase because only one phase of the three-phase winding is energized at a time, and one cycle includes three pulses in total.

2) Features

1. Every time an electric pulse comes, the rotor rotates 30 degrees. This angle is called the step angle, which is represented by the representation (the format limit is placed in Figure 1).

2. The rotation direction of the rotor depends on the order in which the three-phase coils are energized, and the direction can be changed by changing the order of energization.