Views: 12 Author: Site Editor Publish Time: 2016-04-20 Origin: Site
A stepper motor, also known as step motor or stepping motor, is an electromagnetic mechanical device that converts electrical pulse signals into corresponding angular or linear displacements, and is an incremental drive element whose output corresponds to the input digital pulse. In layman's terms, when an electric pulse signal is applied to the control device (driver) of the stepping motor, its shaft will rotate through an angle or advance one step, and the electric pulses will be sent one by one, and the stepping motor will rotate step by step. or move. This kind of motion is different from the motor that rotates evenly after being energized. It is a stepping motion, so it is called a stepping motor, also called a pulse motor. Stepper motors are mainly divided into reactive model (VR), hybrid model (HB) and permanent magnet model (PM) stepper motors.
In addition to the most basic rated data such as: power supply voltage, input current, phase number, and step angle, the performance indicators of stepper motors mainly include the following items:
When the control pulse is continuously input into the control device of the stepper motor, the rotor rotates step by step. When the control pulse stops, but the control winding of a certain phase is still supplied with a constant current, the rotor is locked under the action of the electromagnetic torque of the phase, and the rotor stays in a stable equilibrium position. Even if there is a small fluctuation in this position, the electromagnetic force will pull the device back to this equilibrium position. It reflects the changing law of the static torque and misalignment angle of the stepper motor due to the external torque, which is called the moment-angle characteristic.
The maximum value of the torque in the torque-angle characteristic of the stepper motor under the rated number of energized phases is called the maximum static torque. It indicates the ability of the stepper motor to bear the load. The greater the maximum static torque, the greater the load capacity of the motor, and the better the speed and stability of the operation.
stepper motor can suddenly start without losing step in a static state is called the starting frequency. The starting frequency is related to the motor load torque and moment of inertia. The larger the maximum static torque, the smaller the moment of inertia of the system, the smaller the step angle, and the higher the starting frequency.
After the stepper motor is started, when the control pulse frequency continues to rise, the highest pulse repetition frequency that can run without out of step is called the operating frequency. The factors affecting the running frequency are basically the same as those affecting the starting frequency. But the influence of moment of inertia is relatively small. The moment of inertia mainly affects the speed at which the frequency continues to rise and fall. The drive unit (driver) has a great influence on the operating frequency. A good driver can maximize the operating frequency of the stepper motor, but also achieve low noise and low power consumption.
The torque-frequency characteristic is to describe the curve relationship between the maximum output torque and the pulse repetition frequency of the stepper motor when the load moment of inertia is constant and the steady-state operation is performed. In general, the torque-frequency characteristic of a stepper motor is a descending curve. As the control pulse frequency increases, the output torque decreases and the load capacity becomes smaller. Factors affecting the torque-frequency characteristics include the size and waveform of the control winding current. The driving device (driver) also has a great influence on the torque-frequency characteristics. For a good stepper motor and driver, the torque-frequency characteristic curve drops smoothly.
There are other characteristics, such as starting inertia characteristics, static step angle error, etc.
There is a strict correspondence between the number of input pulses of the stepping motor and its displacement, and the step error will not accumulate.
There is a strict correspondence between the rotational speed during stable operation and the frequency of the input pulse.
Within the range of load capacity, the speed and displacement will not change due to fluctuations in current, voltage, load size, and environmental conditions.
Good control performance. Under a certain frequency, it can quickly start, stop and reverse according to the requirements of the control frequency. By changing the control pulse frequency, the motor speed can be smoothly adjusted in a wide range. Therefore, stepper motors can be widely used in digital-to-analog conversion, speed control and position control systems, and are ideal actuators for open-loop control systems.
The system is simple, the performance is stable, the work is reliable, and the cost is low.
The research and manufacture of stepper motors in China originated in the late 1950s. It was mainly a small number of products developed by colleges and universities and scientific research institutions for the development of some devices. These products are mainly three-phase reactive stepper motors (VR STEPPER MOTOR) Mainly. In the 1970s, the research and production of stepper motors made great progress. By the 1980s, due to the excellent performance of power stepping motors in the field of control, especially CNC machine tools, and the adoption of various new technologies, new processes and new materials, the development of stepping motors entered a higher level, and gave birth to new technologies, especially With the wide use of integrated circuits on stepper motor drivers, the performance of the drivers has also been greatly improved. With the introduction of foreign stepper motor technology (Germany and Japan), from the mid-1980s to the present, hybrid stepper motors have gradually become the mainstream of control stepper motors and power stepper motors. Hybrid stepper motor drivers are integrated The widespread adoption of chips is also developing in the direction of integration, miniaturization, and high subdivision, which greatly improves performance.
With the continuous development of digitization and automation, stepper motors are widely used in various motion control scenarios such as factory automation and office automation. The development of stepper motors is closely related to the development of the computer industry. Since stepper motors are used in computer peripherals Since the replacement of small DC motors, the performance and reliability of computer peripherals such as printers and copiers have been significantly improved. At the same time, the development of computer technology has promoted the application of stepper motors as executive components to other fields, such as aerospace Aviation, electrical machining CNC machine tools, robots, measuring instruments, optical and medical devices, packaging machinery, textile machinery, etc.
The current main products of Henghe Motor are 28, 35, 39, 42, 57, 60 to 86 two -phase HB stepper motors and corresponding stepper motor drivers, 57, 60, 86 and three-phase HB steppers Motor series. The main technicians and management of Henghe Motor witnessed the birth, growth and development of hybrid stepping motors in China, and participated in the application of new technologies, new processes and new materials for various hybrid stepping motors. The performance and reliability have been greatly improved, and the products are widely used in various fields of digital control.
In addition to the 28~86 series hybrid stepper motors, Henghe Motor has also developed closed-loop hybrid stepper motors, linear stepper motors and geared stepper motors (also known as gearbox stepper motor) for different application scenarios, which can improve the controlling precision and stepper’s torque. Multi-model stepper motor drivers have the characteristics of integration, modularization, miniaturization, low noise, high subdivision, low power consumption, etc., and according to different requirement of the CNC equipment or other application scenarios, there will a proper stepper motor to choose. Then it is not only meet the needs of use, but also improves the efficiency and saves the cost for the customer.
Henghe can also offer flexible customization solutions to customers with stable supplying system. OEM and ODM is also acceptable.
For OEM Motor Projects or customization project, we’ll work directly with your engineering team throughout the design phase of your project to ensure the he best overall system optimization and motor fit with reasonable cost.
Stepper motors are different from AC motors and DC motors in the traditional sense. Stepper motors do not have a power rating. The most important indicator for selecting a stepper motor is torque. The maximum static torque is only a reference index, and the running torque is the main index for torque selection. Usually, the motor with the appropriate frame size is selected according to the required torque (that is, the torque of the load). Generally speaking, if the torque is less than 0.8Nm, choose the frame size below 42 (39, 35.28 and other series), if the torque is around 1Nm, choose the 57 and 60 series, and if the torque is several to 10 Nm, choose the 86, 110, 130 and other series. It should also be noted that the actual output torque of the stepper motor is also closely related to the drive current and external voltage of the driver.
The stepper motors used in different scenarios have different speeds and different parameters of the stepper motors. In general, stepper motors decrease as the pulse frequency increases. Compared with ordinary AC motors and DC motors, stepper motors are low-speed control motors, and the general speed is lower than 1200rmp. The important performance of stepper motors lies in their excellent control performance, so the division of stepper motor speeds is not so strict. Generally, we define a stepping motor below 500rpm as a low-frequency stepping motor with a large output torque, 600~800rpm as a medium-frequency stepping motor, and above 1000rpm as a high-frequency stepping motor. Stepper motors in different usage scenarios correspond to different parameters. Generally, low-frequency stepper motors have higher resistance, a few Ω or >10Ω, and inductance >10mh. High-frequency stepping motor resistance < 1 ohm, inductance < 1mh. The high-frequency stepping motor can also be added with an encoder to form a closed-loop stepping motor to prevent the stepping motor from losing step. When choosing a high-frequency stepping motor, the driver should also choose a higher external voltage.
If the stepper motor is required to start and stop frequently in an instant and the speed is >1000rpm, it must be accelerated to start. At this time, it is best to choose a reactive stepper motor (VR STEPPER MOTOR) or a permanent magnet stepper motor (PM STEPPER MOTOR).
Stepper motors have different phases and different step angles. High-phase stepper motors have smaller step angles and higher control accuracy. In high-speed and high-torque working environments, three-phase hybrid steppers can be used. motor. But high-phase stepper motors also cost more. Currently the most widely used is the two-phase stepper motor. With the continuous improvement of the subdivision technology of stepper motor drivers, two-phase stepper motors have been able to meet most of the automatic control scenarios.
Usually the ambient temperature of the stepper motor is -40°~60°, and the air humidity is less than 70%rh. Special design is required for use in special environments, such as low temperature (-50°), high temperature (80~100°), high humidity (95%rh), high salt, high corrosion or underwater, etc. and manufacturing.
In general, the mounting flange of the stepper motor can be selected, the length and diameter of the output shaft can be selected, and holes can be arranged on the end cover. However, if you choose a product that exceeds the existing machine seat size, non-standard stator and rotor punching, special end cover cavity, etc., you must re-open the mold, which will involve high costs.
