What is a stepper motor? Stepper motor principle? Stepper motor subdivision (very easy to understand, beginners must be able to quickly master)
2017-04-13 motor technology and Application
With the development of mechanization, electrification and automation of the production process, various types of special motors have appeared.
The working principle of the motor, the basic principle and general approximate ordinary asynchronous motor and DC motor, but they are in the production process, performance structure, each has its particularity, used for automatic control in the process of.
Generally speaking, the power of these motors is not small, only a small fraction of a watt, but also a large number of tens of watts or hundreds of watts, belonging to the scope of micro motor.
General motors are continuous rotation, and stepper motor is a step by step rotation, it is called stepper motor. Each input pulse impulse signal, the motor will turn a certain angle (some stepper motor can be directly output line displacement, known as linear motor). So the stepping motor is a kind of executive element that changes the pulse into angle displacement (or linear displacement).
Rotor stepping motor stator polar distribution, embedded multi phase star control winding connected by the input pulse signal, the electric power special, one for each input pulse signal, the rotor stepping motor will step forward. Because the input is a pulse signal, the output angular displacement is intermittent, so also known as the pulse motor.
With the development of digital control system, the application of stepping motor will be enlarged.
There are many kinds of stepping motors, according to the structure can be divided into two types of reaction and incentive; according to the number of points can be divided into single-phase, two-phase and multi-phase of the three.
Figure 1 is a schematic diagram of the reactive stepping motor, the stator has a uniform distribution of the six poles, winding around the pole. The two opposing poles form a group, as shown in the figure.
This paper introduces the basic principle of the reactive stepping motor single three, six, and two - way three - way.
First, the basic principle of a single three beat power mode
The A phase is connected to the A-A (B, C), which generates the magnetic flux in the axial direction and forms a closed loop through the rotor. At this time, A, A 'pole becomes an electromagnet N, S pole. The effect of the magnetic field, the rotor is always trying to go to the minimum reluctance position, that is to go to the rotor tooth alignment of A and A 'pole position (Figure 2a); and B (A and C two phase electricity electricity turned), then turned 30 degrees clockwise, its teeth and C, C' polar alignment (Figure 2C). It is not difficult to understand that when the pulse signal is sent one by one, if the A, C - B - A ~ ~ in the order of power, the motor rotor will rotate counterclockwise. This way is called a single three way.
Two, the basic principle of six power mode
The A phase is first energized and the rotor teeth are aligned with the stator A, A '(Figure 3a). The A phase is then connected to the B phase when the power is on. At this time the stator B, B 'pole rotor teeth 2, 4 magnetic pull force, so that the rotor clockwise rotation, but A, A' pole continues to pull the teeth of 1, 3, therefore, the rotor to the balance of the two magnetic tension.
At this point the position of the rotor as shown in Figure 3B, that is, from the rotor (a) position clockwise turn 15 degrees. Then the A phase power down, B phase continues to electrify. At this time the rotor teeth 2, 4 and the stator B, B 'pole alignment (Figure C), the rotor from the map (b) and turned the position of 15 degrees. Its location is shown in Figure 3D.
In this way, according to A, AB, B, BC, C, CA, A, in turn, turn on the power, then the rotor will be clockwise step by step, the step angle of 15 degrees. The current is changed six times, the magnetic field rotates for a week, and the rotor has a tooth angle. If the A, AC, C, CB, B, BA, A, in the order of power, the motor rotor counterclockwise rotation. This power is called the six beat mode.
Subdivision: after the A is connected to the B, the B phase is not fully energized, and the rotation angle can be achieved by controlling the current size of the phase coil.
Three, the basic principle of the double three power mode
If each time is two interlinked, that is, according to A, B, B, C, C, A, A, B, the order of power, is called the double three beat, from Figure 3B, and figure 3D visible, the step angle is 30 degrees.
Therefore, the single shot three and double three clap when rotor three steps forward a tooth angle, every step forward 1/3 tooth angle; using six shot mode, the rotor six steps forward a tooth angle, every step forward 1/6 tooth angle. Therefore the step angle theta can be calculated by the following: theta = 360 * /Zr * m
Type Zr is the number of rotor teeth; m is the number of runs.
The most common stepper motor step angle is 3 degrees or 1.5 degrees. From the above can be seen, the rotor is not only 4 teeth (tooth angle of 90 degrees), and there are 40 teeth (tooth angle of 9 degrees). In order for the rotor teeth to be aligned with the stator teeth, the tooth width and the pitch must be equal. Therefore, in addition to the stator 6 pole outside, there are 5 in each pole and rotor tooth like denticles. The structure of the stepping motor is shown in figure 4.
It can be seen from the above that the stepping motor has the advantages of simple structure, convenient maintenance, high accuracy, sensitive starting and accurate parking. In addition, the speed of the stepper motor depends on the frequency of the electric pulse, and the frequency synchronization.
Four, stepper motor drive power supply
Step motor need to configure a dedicated power supply, power supply is to control the winding of the motor is energized in a specific order, namely the input electric pulse control and action, the special power called power supply. Stepping