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A BLDC motor (brushless DC motor) is a rotating motor with permanent magnets in the rotor and windings as part of the stator. The BLDC motor replaces the mechanical commutator on a brushed DC motor with an electric commutator, powered by a DC power supply through an integrated inverter/switching power supply, which generates an AC signal to drive the motor. BLDC motors have high efficiency as well as good operability and are widely used in various transmission industries, and expect the low power consumption it brings. DC Motor (Brushed Motor) A coil is placed in a magnetic field, and by flowing current, the coil is repelled by the magnetic pole on one side while being attracted by the magnetic pole on the other side, and rotates continuously under this action. The current flowing backwards into the coil during rotation keeps it rotating. The commutator part of the motor is powered by the brushes, which are positioned above the commutator and move continuously with rotation. By changing the position of the brushes, the current direction can be changed. The commutator and brushes are indispensable structures for the rotation of DC motors. BLDC Motor BrushLess” in BLDC motors means “brushless”, which means that the brushes in DC motors (brushed motors) are not present. The role of brushes in DC motors is to energize the coils in the rotor through the commutator, but BLDC motors use permanent magnets for the rotor, and there are no coils in the rotor. The DC motor (brushed motor) has a magnetic field created by a fixed permanent magnet that does not move, and rotates by controlling the magnetic field generated by the coil (rotor), and changes the number of rotations by changing the voltage; the rotor of the BLDC motor is a permanent magnet, and rotates by changing the direction of the magnetic field generated by the surrounding coil, and controls the rotation of the rotor by controlling the direction and magnitude of the current flowing to the coil. Advantages of BLDC Motors BLDC motors have more than three coils on the stator, with two wires per coil, for a total of at least six lead wires in the motor. In fact, because it is internally wired, usually only three wires are needed, but still one more than the previously described DC motor (brushed motor), which does not move by connecting the positive and negative terminals of the battery. High efficiency, you can control the gyratory force (torque) always maintain the maximum, DC motor (brush motor) rotation during the maximum torque can only be maintained for a moment, can not always maintain the maximum. If a DC motor (brushed motor) wants to get as much torque as a BLDC motor, it can only increase its magnet, that’s why even a small BLDC motor can give out great power. Good control, BLDC motor can get the torque and rotation number you want without any difference, BLDC motor can feedback the target rotation number and torque precisely, and the heat and power consumption of the motor can be suppressed by precise control. If it is battery driven, it can prolong the driving time by well-controlled. Durable and low electrical noise. DC motor (brushed motor) will have loss due to the contact between brushes and commutator for a long time, and the contacted part will also generate sparks, especially when the gap of commutator touches the brushes, there will be huge sparks and noise. If you do not want to make noise during use, you will consider using a BLDC motor. Uses of BLDC Motors What is the general use of BLDC motor with high efficiency, various control, and long life? They are often used in products that can make use of their high efficiency and long life, and are used continuously. For example, BLDC motors have recently been used in electric appliances and electric fans, and have succeeded in significantly reducing power consumption because of high efficiency. By changing the control system, a significant increase in the number of rotations has been achieved. The vacuum cleaner demonstrates the good control of the BLDC motor. The hard disk, which is an important storage medium, also uses a BLDC motor for its rotating part. Since it is a motor that needs to run for a long time, durability is important. It also has the use of extremely suppressed power consumption, and high efficiency is also related to low power consumption. Conclusion Brushless motor has many advantages over brushed DC motor, including high torque to weight ratio, higher torque (higher efficiency), higher reliability, lower noise, longer life (brushless and commutator corrosion), elimination of ionizing sparks generated by commutator, and overall reduction of electromagnetic interference. Since the windings are supported by the housing, they can be cooled by conduction, eliminating the need for airflow inside the motor for cooling, which in turn means that the interior of the motor can be completely enclosed to prevent dust or other foreign objects from entering. BLDC motors will be more appropriate for small robots, in terms of force control. If stepper motors are used, a structure such as a robot wrist to be fixed in a certain position requires BLDC motors are also suitable for use in drones, especially those with multi-axis racks, as it is possible to control the flight attitude by changing the number of rotations of the propeller, so BLDC motors that can precisely control the rotation are advantageous.

The rotor inside the servo motor is a permanent magnet. The U/V/W three-phase electricity controlled by the drive forms an electromagnetic field, and the rotor rotates under the action of this field, while the encoder that comes with the motor feeds back signals to the drive, which adjusts the angle of rotor rotation according to the feedback value compared with the target value. The accuracy of the servo motor is determined by the accuracy of the encoder (number of lines). What is a servo motor? How many types are there? What are the working characteristics? A: Servo motor, also called actuator motor, is used as an actuator in the automatic control system to convert the received electric signal into angular displacement or angular velocity output on the motor shaft. It is divided into two categories: DC and AC servo motors. Its main feature is that there is no self rotation when the signal voltage is zero, and the speed decreases uniformly with the increase of torque. What is the difference in function between AC servo motor and brushless DC servo motor? A: AC servo is better, because it is a sine wave control ball screw, torque pulsation is small. DC servo is trapezoidal wave. But DC servo is simpler and cheaper. Permanent magnet AC servo motor Since the 1980s, with the development of integrated circuits, power electronics and AC variable speed drive technology, permanent magnet AC servo drive technology has developed prominently, and famous electrical manufacturers in various countries have launched their own AC servo motor and servo drive series products and continue to improve and update. AC servo system has become the main development direction of the contemporary high-performance servo system, so that the original DC servo facing the crisis of being eliminated. 90s later, the world has commercialized the AC servo system is the use of fully digital control of the sine wave motor servo drive. The development of AC servo drive in the field of transmission is changing day by day. Compared with DC servo motor, the main advantages of permanent magnet AC servo motor are: (1) No brushes and commutator, so it works reliably and requires low maintenance and care. (2) The heat dissipation of stator winding is more convenient. (3) Small inertia, easy to improve the rapidity of the system bellows coupling. (4) Adapt to high speed and high torque working condition. (5) With the same power has a smaller volume and weight. Servo and stepper motor Servo mainly relies on pulse to position, basically can be understood in this way, the servo motor receives 1 pulse, it will rotate 1 pulse corresponding to the angle, so as to achieve displacement, because, the servo motor itself has the function of sending out pulses, so the servo motor will send out a corresponding number of pulses for each rotation angle, so that, and the servo motor receives pulses to form an echo, or closed loop, in this way The system will know how many pulses were sent to the servo motor and how many pulses were received back at the same time, so that it can control the rotation of the motor very precisely and thus achieve precise positioning, which can reach 0.001mm. Stepper motor is a discrete motion device, which has an essential connection with modern digital control technology. In the current domestic digital control system, stepper motors are widely used. With the emergence of fully digital AC servo systems, AC servo motors are also increasingly used in digital control systems. In order to meet the development trend of digital control, most of the motion control systems use stepper motors or fully digital AC servo motors as the execution motor. Although the two are similar in the control mode (pulse string and direction signal), flexible coupling, but there are major differences in the use of performance and application occasions. Now, the use of the two performances for a comparison. First, the control accuracy is different Two-phase hybrid stepper motor step angle is generally 3.6 °, 1.8 °, five-phase hybrid stepper motor step angle is generally 0.72 °, 0.36 °. There are also some high-performance stepper motor step angle is even smaller. For example, a stepping motor for slow-walking machine tools produced by SCT, its step angle is 0.09 °; Germany BERGER LAHR company (BERGER LAHR) produced a three-phase hybrid stepping motor whose step angle can be set to 1.8 °, 0.9 °, 0.72 °, 0.36 °, 0.18 °, 0.09 °, 0.072 °, 0.036 °, compatible with the step angle of two-phase and five-phase hybrid stepper motors. The control accuracy of the AC servo motor is guaranteed by the rotary encoder at the rear of the motor shaft. For a Panasonic fully digital AC servo motor, for example, the pulse equivalent is 360°/10000=0.036° for a motor with a standard 2500-line encoder due to the quadruple frequency technology used inside the drive. For a motor with a 17-bit encoder, the drive receives 217=131072 pulses per motor revolution, i.e., its pulse equivalent is 360°/131072=9.89 seconds. Is the step angle of 1.8 ° of the stepper motor pulse equivalent 1/655. Second, the low frequency characteristics are different Stepper motor at low speeds are prone to low-frequency vibration phenomenon. Vibration frequency and load conditions, and drive performance, it is generally believed that the vibration frequency is half of the motor no-load starting frequency. This low-frequency vibration phenomenon determined by the working principle of the stepper motor is very unfavorable to the normal operation of the machine. When stepper motors work at low speeds, damping technology should generally be used to overcome the low-frequency vibration phenomenon, such as adding dampers on the motor, or subdivision technology on the drive, etc. AC servo motor operation is very smooth diaphragm coupling, even at low speeds, there is no vibration phenomenon. AC servo system has resonance suppression function, which can cover the lack of mechanical rigidity, and the system has internal frequency resolution function (FFT), which can detect the resonance point of the

There are many uses of servo motors, and we want to figure out where servo motors will be used. Then the principle of the motor, to say a little about the function of the motor. For those who are new to industrial automation, or those who are new to machinery, what exactly does a servo motor mean? In fact, a very simple understanding is that the motor can be precisely calculated how much angle rotation, and can do real-time position feedback. Does it feel like the motor is being monitored by something in real time? It is the encoder that monitors the motor. So, the characteristics of the servo motor are very distinctive, the servo characteristics determine the servo motor will be used in which equipment above. 1, high precision. High precision can control the position. 2, closed-loop control response is fast. Fast response can control the change of frequency and strength. 3, the entire motor movement is controlled, then the entire motor can be programmed through the digital signal, or pulse signal, to achieve the control. That is, complex motion. Do not see this feeling or can not understand? The talk you will understand. We will give the above three major features to translate into various movements in the industrial field. 1, Feature one: position control. Since it can do a very accurate alignment work, it is not possible to do: labeling, do two product alignment lamination, do promotional table. Is it possible to control multiple products at the same time to form a regular movement, for example, the light ball above the stage. Is it possible to be very accurate in the printing machine, horizontal and vertical sewing, is it possible to do sawing? So when we encounter any equipment that needs to be very accurate, we should first think of using a servo. As for the final product design, the use of servo motors, or stepper motors, depends on the cost and accuracy requirements of the degree. The accuracy of servo motor is much higher than that of stepper motor, a 17-bit encoder servo motor can reach 600 times the accuracy of an ordinary stepper motor. Among the devices that mainly reflect the servo position mode are: Quilting and quilting machines, printing machines, dispensing machines, laminating machines, labeling machines, laminating machines, inspection and conveying tables in the field of electronic manufacturing, various types of transmission line bodies, shift machines, and various types of applications of flying shear chasing shear. The hottest servo motor used on the top of the mask machine in 2020 is a 750W servo, controlled by PLC or motion controller, the main thing is the tension control (you can simply understand it as an advanced version of the position control mode) achieved by dragging the motion of the raw material strip of the mask. For many friends just engaged in this line, if you look at a device to use servo, you ask each other the processing accuracy of this thing, whether it needs to be very high. If it does not need to be very high, then basically stepper motors may be fine. 2, Feature two: closed-loop control-related applications. In fact, closed-loop control response fast, this feature, we can first think of a variety of valves, switch applications is not it? Then congratulations, you did answer the right. Take our hottest ventilator now, the ventilator in the air and oxygen mixing time, is the use of servo valves. In the corresponding fast, we first found the application area is: a variety of machine tools, where you just see the frequent change of speed, or the frequent change of position of the machine tool, basically use servo motors to provide power. For example: all the axes of the 5-axis machine tools are servo-driven, which are mainly to provide position control. The second largest application market is the industrial robot market. An industrial robot uses six servo motors, whose precision control and high responsiveness are very high. In the rapid corresponding application of equipment such as: turning, milling, grinding, CNC-type machine tools, servo turret punch, bending machines, laser cutting machines, etc.. There are all kinds of industrial robots, collaborative robots, and AGV carts that use servo motors. 3, The characteristics of three: the precise control of continuous motion. This feature is mainly a sublimated version of the first two features. For example: a 2000-ton servo press, you can do 20000N-m pressure above, he can control in real time, which is the servo can control. Another example: wire cutting equipment, this type of equipment is extremely common in the stone, polysilicon, and other markets. This is a typical representative of the continuous reciprocating motion in the ability to achieve precise control. If you must explain the application of servo motor scenario in general: control output force (professional name called torque) can be large or small, while the force can be done to change very uniformly rise and decrease. That is to say, not only the final result can be controlled, but also to control the process of no point. The following is the selection of servo motors: There are many people will be in, servo motor can be used in which areas, when the servo mentioned constant speed, constant power. In fact, the constant speed and power of the servo is the parameter that will be considered only at the time of selection. To say something more pleasing, if you intend to design a device, you already have parameters about the production frequency of the device, and other electrical equipment. Then you don’t know about servo motors, just go directly to a manufacturer of servo motors. Directly let people give you the selection of adapters. This will not want you to put in the effort to calculate. If you do want to calculate yourself, how to select the servo motor, then you need to know basically how much torque is needed. In general, the equipment in the design process, is a general understanding of how

Variable frequency motor refers to the motor which runs continuously with 100% rated load in the range of 10%~100% rated speed under standard environmental conditions and whose temperature rise does not exceed the allowable value of the motor calibration. With the rapid development of devices, AC speed regulation technology has been constantly improved and improved, gradually improved frequency converter with its good output waveform, excellent performance and price ratio has been widely used in AC machines. For example, the large motor used for steel rolling, the medium and small roller table motor, the traction motor for railway and urban rail transit, the elevator motor, the lifting motor for container lifting equipment, the motor for water pump and fan, the compressor, the motor for household appliances and so on all use AC frequency conversion speed regulating motor successively, and have achieved good results. The AC frequency conversion speed regulating motor has significant advantages over the DC speed regulating motor: (1) Easy speed regulation, and energy saving. (2) AC motor has the advantages of simple structure, small size, small inertia, low cost, easy maintenance and durability. (3) Can expand the capacity to achieve high speed and high voltage operation. (4) Can achieve soft start and fast braking. (5) No spark, explosion-proof, strong adaptability to the environment. Constant frequency motor Fixed-frequency motors usually refer to the fixed frequency (50Hz) at which the motor operates on the power grid and cannot be used for frequency modulation. Because of the difference in the structure of the motor, such as the motor being more than a heat dissipation fan. The difference between a washing machine variable frequency motor and a fixed frequency motor 1, a frequency conversion washing machine can adjust the motor washing and dehydration speed by adjusting the voltage, but also according to the type and texture of clothing to choose the right washing water flow, washing time, dehydration speed, dehydration time. Because the inverter washing machine adopts direct drive motor, it avoids the use of transmission belt and other transmission parts, which further reduces the failure rate of washing machine and greatly reduces the noise of motor. In addition, in the whole washing process, the application of frequency conversion technology can control the speed of the motor, which can not only save energy and electricity, but also reduce the damage to clothes, reducing the winding and wear of clothes. 2, Once the fixed-frequency washing machine starts to work, the speed of the motor will remain the same and keep turning until it is turned off. Continuous high-speed operation not only consumes electricity, but also causes great damage to clothing, which often causes knots. Because the fixed frequency washing machine program setting is simple, the washing process is relatively simple, the price is low. Compared with ordinary fixed-frequency washing machines, frequency conversion washing machines are more expensive, but they are energy efficient and can bring users a greener and healthier laundry experience. 3, from the washing effect, there is progress is sure. Frequency conversion washing machine means that the motor used is frequency conversion, which is reflected in the washing machine that the speed of the drum is adjustable. For example, if you wash less clothes or are not too dirty, you can wash them with low speed. Of course, low speed consumes less electric energy. The motor used in traditional washing machines is a fixed-speed motor, that is to say, as long as you turn on the power, the motor will rotate at a certain speed, no matter how many clothes you wash with this speed, of course, the power consumption is also fixed. Therefore, frequency conversion should be relatively energy-saving.

DC motors have a wide range of applications and are often used in harsh environments, such as humid, high temperature, dusty, corrosive, etc. Therefore, in addition to the proper use, the protection link of it is an indispensable part of the electrical control system, and proper protection can extend its life. Its protection is to ensure the normal operation of the motor, prevent damage to the motor or mechanical equipment, and protect personal safety. Here, Leili will tell you in detail. 1. DC motor operating precautions (1) Check whether the commutator’s appearance can be bright before use, there should be no mechanical damage and spark burn marks. (2) Check whether the brush has been worn too short, whether brush grip pressure is appropriate (usually the pressure should be 150-200 g/cm?), check whether the brush holder orientation is by following per under the specified symbol. (3) The spark on the commutator during operation should not be greater than 1/4-1/2 level. 2. DC motor protection time (1) Monthly protection: check the carbon brushes and rectifiers, do a good job of cleaning, replace the fan screen if necessary. Check whether all collector rings, DC motors, and collectors can work correctly, and check the thickness of wiring on terminals and parts. Check whether there is water inside the main electric cabinet and DC motor. (2) Protection of each quarter: check the bearings (temperature, boo,m and noise). Check the insulation to the ground with a shaking table (not less than 2 megohms) (3) Every six months of protection: dry airflow to clean the rectifier and windings. Check the electrical articulation and all the screws. In winter time, in order to adhere to the temperature of the motor, the following voltage (30-50V) can be supplied to the excitation. 3. Protection measures of DC motor (1) Short-circuit protection When the short-circuit fault is caused by insulation damage of the motor winding and wire, damage to the control appliance and line, or the misoperation of touching the line, the measure of using the protection appliance to cut off the power quickly is short-circuited protection. Commonly used short-circuit protection appliances are fuses and automatic air circuit breakers. (2) Undervoltage protection When the grid voltage decreases, the motor will run under undervoltage. Since the motor load is not changed, the motor torque decreases, and the stator winding current increases, which affects the normal operation of the motor and even damages the motor. Under-voltage protection is achieved by contactors and electromagnetic voltage relays. The fuse and thermal relay can’t protect the under-voltage, because when the motor is running under the under-voltage, the stator winding will increase. The magnitude of the stator winding increase is not enough to make the fuse and thermal relay operate, so these two appliances can’t carry out the under-voltage protection. (3) Loss of voltage protection When the production machinery is working, for some reason, the power grid suddenly stops, when the power supply is restored, the protection apparatus should ensure that the production machinery can run after restarting, so as not to cause personal and equipment accidents, this protection is loss of voltage (zero voltage) protection. The electrical appliances to achieve the loss of voltage (zero voltage) protection are contractors and intermediate relays. (4) Weak magnetic protection The protection apparatus is used to ensure that the DC motor works under a certain strength of the magnetic field. So that the magnetic field will not be weakened or disappear. The motor speed will not be increased rapidly, and even the flying phenomenon will occur. In the excitation circuit of DC motor, a weak magnetic relay (i.e. under-magnetization relay) is connected to the DC motor. The weak magnetic protection can be realized by adding a weak magnetic relay (i.e. under the current relay) in series. Working principle of under current relay: in the process of DC motor starting and running, when the excitation current value reaches the action value of under current relay, the relay will absorb and make the normally open contacts in the control circuit close, allowing the motor to start or maintain normal operation. But when the excitation current decreases a lot or disappears, the undercurrent relay will release and the normally open contacts will break, cutting off the control circuit and the contactor coil will be de-energized and the motor will stop. When the excitation current decreases a lot or disappears, the under-current relay will be released and its normally open contact will be broken to cut off the control circuit. (5) Overload protection When the motor load is too large and the starting operation is frequent or the phase is not running, the motor current will exceed its rated current for a long time, which will shorten the motor life or damage it. When the motor is overloaded, the measure to cut off the power with the protection apparatus is overload protection. (6) Over-current protection The protection apparatus is used to limit the starting current or braking current of the motor so that the motor will run under the safe current value, which will not cause damage to the motor or mechanical equipment. Generally, an electromagnetic over-current relay is used to achieve over-current protection. Easy to generate overcurrent situation: additional resistors are strung into the armature winding of DC motor and rotor winding of the three-phase AC wire-wound rotor asynchronous motor to limit the motor starting or braking current. If the additional resistors are shorted during starting or braking, it will cause a large starting current or braking current. In this case, overcurrent is easy to occur. The method of implementing overcurrent protection: the coil of the electromagnetic overcurrent relay is connected in series in the main circuit and its normally closed contact is connected in series in the control circuit. When the overcurrent value of the motor reaches the auction value of the overcurrent relay, its normally closed contact disconnects the control circuit and stops the motor from a power supply, thus realizing the overcurrent protection. The difference between overload protection and

Geared Stepper Motor Structure: A geared stepper motor is a standard stepper motor with an output shaft connected to a gear box. The gearbox provides high torque and low speed output through reduction gear transmission. Features: Provides high torque, low speed and precise positioning. With a reduction gear drive, higher output torque can be achieved for applications requiring precise position control and larger loads. Applications: Robotics: Micro geared stepper motor is often used in robot joints and actuators. Since the robot requires precise position control and stable motion, these motors provide high torque through gearing to cope with mechanical loads while maintaining precise stepping resolution for accurate attitude and motion control. Numerical Control Machine tools (CNC): In CNC machine tools, gear-type stepper motors are used to control the position of the tool, tables, and other moving parts. They provide enough torque to handle cutting and machining operations, and they ensure that the workpiece remains in a precise position during machining. Conveyor systems: In automated conveyor systems, a stepper motor with a gear box can be used to control the movement and stopping of conveyor belts, as well as to position objects when needed. Since delivery systems often require precise object positioning and fast stop/start operations, the high torque characteristics of these motors are very valuable in these applications. Medical devices: Stepper gearbox has a wide range of applications in medical devices, such as motion control for X-ray robotic arms, joint control for surgical robots, and precision positioning tasks in drug distribution devices. Laser cutting and engraving machines: In equipment where laser tools need to be precisely positioned for cutting and engraving, geared stepper motors can provide the precise control required to ensure high-quality cutting and engraving results.   Hybrid Stepper Motor Structure: The hybrid stepper motor combines the two principles of permanent magnet and variable reluctance. The rotor usually consists of a permanent magnet and a winding on the stator. Features: Delivers high torque and speed performance, as well as relatively high step resolution. More flexible than permanent magnet stepper motors for applications where torque, speed and precision need to be balanced. Applications: Numerical Control Machine tools (CNC): In CNC machines, a hybrid servo stepper motor is used to control the position of the tool and the table. Because these motors can provide high-precision position control and smooth motion, they are essential for the control of machining processes such as engraving, cutting, milling, etc. Medical equipment: Hybrid type stepper motor plays a key role in medical equipment, such as moving parts in medical imaging equipment, positioning of drug distribution equipment, joint control of surgical robots, etc. In these applications, high-precision and reliable motion control is essential for patient safety and therapeutic outcomes. Automation and robotics: In the field of industrial automation and robotics, hybrid synchronous stepper is often used in robot joints and actuators, as well as in automation systems that require highly precise control. These motors offer good dynamic performance and positioning accuracy. Experimental equipment and scientific research instruments: In scientific research and experimental equipment, the need for high-precision motion control is very common. Hybrid stepper motors are used for sample movement and adjustment in equipment such as microscope platforms and experimental platforms for various tests and observations. Precision instruments and optical equipment: High-precision position control is essential to the performance of precision instruments and optical equipment. Hybrid stepper motors are used in telescopes, laser equipment, spectrometers, and other equipment to ensure stable movement and accurate positioning of the equipment. 3D printing and rapid prototyping: In the field of 3D printing and rapid prototyping, hybrid stepper motors are used to control the position of print heads and tables to enable complex printing and manufacturing processes. Permanent Magnet Stepper Motor Structure: PM stepper motor has a permanent magnet on the rotor and an electromagnetic coil on the stator. When energized, the electromagnetic coil generates a magnetic field that interacts with the permanent magnet on the rotor, which drives the stepping motion. Features: Relatively simple and low cost, suitable for applications requiring moderate torque and low speeds. However, performance may be limited at high speeds and high loads. Applications: Printers and plotters: Permanent magnet stepper motors are often used in printers and plotters to control the position of the print head. These motors provide enough precision to ensure fine print or drawing while being suitable for relatively low speed and load requirements. Automation small tasks: In some small automation tasks, such as automatic doors, vending machines, automatic display stands, etc., permanent magnet stepper motors can provide moderate positioning control and motion functions. Household appliances: Permanent stepper motor is widely used in some household appliances, such as the rotating plate of a microwave oven, the washing bucket control of a washing machine, and the bread rack rise in a toaster. Medical equipment: In some medical equipment requiring lower costs, permanent magnet type stepper motor can be used to control the moving parts of medical equipment, such as bed position adjustment, drug distribution devices, etc. Mechanical instruments: In some medium-precision mechanical instruments, such as test equipment, small machine tools, etc., permanent magnet stepper motors can provide sufficient positioning accuracy and motion control. Small robots: In some small robots that require simple position control, permanent magnet stepper motors can provide basic motion control capabilities.