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Background technique: The electric drying racks on the market have a short air outlet and a fixed direction, so the drying efficiency is low; the electric drying racks have a small blowing range, and the wind direction blown by the fan may not completely blow to the clothes, causing waste. Technical realization elements: The new technical problem is to provide an electric drying rack stepping motor control device applied to the air outlet of the electric drying rack, which can make the wind blown by the fan of the electric drying rack completely blow toward the clothes and improve the drying efficiency. The new type of electric drying rack stepping motor control device includes an electric drying rack body and a connecting rod, a fan, and a signal module for receiving remote control signals, and controlling the fan to turn on according to the remote control signal, and at the same time controlling the stepping motor to rotate and set the angle, Make the cut surface of the fan windshield just tangent to the MCU controller on the edge of the conjoined drying rod; the fan windshield is a double-open windshield, including a left windshield and a right windshield, and is set in the direction of the clothes dryer body The central position on one side of the connecting rod. The stepping motor of the electric drying rack controls the rotation of the wind deflector of the fan through a gear set to control the opening angle of the air guide opening of the fan; the gear set includes a first driving wheel and a second driving wheel that are engaged with each other. The meshing first driven wheel and the second driven wheel meshing with the second driving wheel; the center of the first driving wheel is provided with a gear groove matching the shaft of the stepping motor. One end of the left wind deflector is fixedly connected to the first driven wheel, and one end of the right wind deflector is fixedly connected to the second driven wheel; when the rotation setting angle of the stepping motor of the electric drying rack is 0°, the left windshield The distance between the other end of the wind panel and the other end of the right wind deflector is the smallest, that is, the air guide opening of the fan is closed.

The structure and principle of high-speed dome camera The high-speed dome camera is a highly integrated product that integrates the pan-tilt system, communication system, and camera system. The pan-tilt system refers to the driving part of the rotation, and the communication system refers to the control of the motor and the image and signal In the processing part, the camera system refers to the all-in-one movement. Between several major systems, the main control core CPU and power supply are connected horizontally. The power supply part is powered by the major systems. In many places, diodes, triodes and other micro-current power supply are used, and the core CPU is the basis for the normal operation of all functions. The principle of the high-speed dome camera is roughly what is mentioned above, and specifically, the high-speed dome camera adopts "precision differential high-speed dome camera stepping motor" to realize the fast and accurate positioning and rotation of the high-speed dome. All of this is achieved through instructions issued by the CPU. Then write the image of the camera and the functions of the camera into the CPU of the high-speed dome. When controlling the PTZ, the image can be transmitted, and many functions of the camera, such as white balance, shutter, aperture, zoom, and focus, can be transferred. And other functions can be controlled at the same time. General high-speed dome cameras are divided into the center part, the shell part and the accessories part. Any manufacturer`s high-speed dome has a sphere center part that uses a frame to unify the package all-in-one machine core, control decoding motherboard and motor pan/tilt system, and then the sphere center part and the shell are connected with screws or other methods. The center of the sphere is the core part, and the shell generally has a variety of appearances, such as the appearance of Pelco, the appearance of Panasonic, and the appearance of its own design. The shell is generally made of aluminum alloy, but also plastic. Aluminum alloy is generally divided into two kinds of shells: casting and stamping. Aluminum alloy is better than plastic, and stamping is better than casting. The lower shell is a transparent cover. The transparent cover must be an optically transparent cover to ensure that the light transmission rate and image are not deformed. At the same time, anti-aging, anti-vandalism, dust-proof and other issues must be considered. The accessory part generally includes a bracket part, a heater part, and a fan heating part. Brackets include wall mount brackets, boom brackets, surface mount ceilings, and embedded ceilings. No brackets are required. Generally, outdoor balls are equipped with fan heating devices, while heating devices are only optional in severe cold areas. Indoor high-speed dome cameras In principle, there is no heat dissipation and heating part. Accessories also include a power supply, which is generally powered by a 24 volt 2 to 3 ampere transformer. The high-speed dome camera has several main hardware components, first, then the slip ring, then the power supply and the control board. The driving belt is also very important. The communication problem of the high-speed dome camera is also related to the communication protocol and communication method. The communication protocol refers to the communication protocol selected when the high-speed dome camera communicates with the host system, such as pelco, Manchester code, Panasonic, Phillips, etc. The communication method refers to the communication method used by these communication protocols, such as 485 communication method, 232 communication method, 422 communication method, and coaxial video control communication method. Generally speaking, high-speed dome adopts 485 communication method, and each communication protocol Different manufacturers.

1. Step angle: Each time the stator winding of the stepper motor changes its power state, the angle at which the rotor turns is called the step angle. The more the number of rotor teeth, the smaller the step angle; the more the stator phases, the smaller the step angle; the more the beat of the energization mode, the smaller the step angle. Step angle θ=360°/(number of rotor teeth×number of running beats). The step angle of the motor indicates the angle of rotation of the motor every time the control system sends a pulse signal. In other words, the angle that the rotor rotates for each input pulse electric signal is called the step angle, which is represented by θ. Take a conventional two-phase and four-phase motor with a 50-tooth rotor as an example. The step angle is θ=360 degrees/(50×4)=1.8 degrees (commonly known as full step) in four-beat operation, and the step angle is θ=360 degrees/(50×8)=0.9 degrees in eight-beat operation. Half step). Extended information The stepping motor has a fixed resolution. For example, a stepping motor with a resolution of 24 steps per revolution has a step angle of 15°. The advantages of using a small step angle to complete a certain incremental movement in several steps are: the amount of overshoot during operation is small, the oscillation is not obvious, and the accuracy is high. When selecting, the accuracy and speed requirements of the system should be weighed. The common ones are 3°/1.5°, 1.5°/0.75°, 3.6°/1.8°. For example, for a stepping motor (small motor) with a step angle of 1.8 degrees, the number of pulses used for one revolution is n=360/1.8=200 pulses. The error of the step angle will not accumulate for a long time, and only corresponds to the number of input pulse signals. It can form an open-loop control system with a relatively simple structure and a certain precision, or a closed-loop system when higher precision is required. The step angle can be measured directly by using precision angle measuring equipment such as a reading microscope and photoelectric encoder to measure the angle that each pulse has turned. Since the stepping motor receives a pulse signal, it must rotate a certain angle accordingly. In the inspection test, the method of preset pulse number Nf can also be used to check the number of steps per revolution to indirectly check whether the step angle is correct. 2. Related conclusions ⑴. Controlling the energization sequence of the stator windings of the stepping motor can control the direction of rotation of the stepping motor; ⑵, control the frequency of the pulse input to the stepper motor can control the speed of the stepper motor; ⑶, control the number of pulses input to the stepper motor can control the angular displacement of the stepper motor. 3. The relationship between torque and speed Speed formula: n=60f/P (n=speed, f=power frequency, P=number of magnetic pole pairs) Torque: The torque that makes a mechanical element rotate is called rotational torque, or torque for short. Mechanical components will produce a certain degree of torsional deformation under the action of torque, so torque is sometimes called torque. Torque formula: T=9550P/n T is the torque in N·m P is the output power in KW n is the motor speed, unit r/min The specific derivation relationship is as follows: 1) Power = Force * Speed That is: P=F*V Formula 1 2) Torque (T) = Torque (F) * Radius of action (R) That is: T=F*R Through the above formula, you can deduce F=T/R formula 2 3) Linear velocity (V)=2πR*rotation speed per second (n seconds)=2πR*rotation speed per minute (n minutes)/60=πR*nminute/30 Formula 3 Substituting formulas 2 and 3 into formula 1, we get: aP=F*V=(T/R )*(πR*n/30) =(π/30)*T*n P=power unit W, T=torque unit Nm, n minutes=rotation per minute unit revolution/minute If the unit of P is changed to KW, then the formula is as follows: P*1000=π/30*T*n 30000/ π*P=T*n 30000/3.1415926*P=T*n 9549.297*P=T*n

(1) When the stepper motor is in operation, pulse signals are applied to the windings of each phase in turn in a certain order (the ring distributor in the drive controls the winding on and off). (2) Even if it is the same stepping motor, when using different drive schemes, its torque-frequency characteristics are quite different. (3) The highest temperature allowed on the surface of the stepper motor: If the temperature of the stepper motor is too high, it will demagnetize the magnetic material of the motor, and then cause the torque to drop and even lose step. Therefore, the highest temperature allowed on the surface of the motor should depend on the different magnetic materials of the motor. Generally speaking, the demagnetization point of magnetic materials is above 130 degrees Celsius, and some even up to 200 degrees Celsius, so the surface temperature of the stepper motor is completely normal at 80-90 degrees Celsius. (4) The stepper motor has no stacking errors: the accuracy of the general stepper motor is three to five percent of the actual step angle, and it does not accumulate. (5) The torque of the stepper motor will decrease with the increase of the speed: when the stepper motor rolls, the inductance of each phase winding of the motor will form a back electromotive force; the higher the frequency, the greater the back electromotive force. Under its effect, the phase current of the motor decreases as the frequency (or speed) increases, and then the torque decreases. (6) The stepper motor is different from other motors. Its nominal extra voltage and extra current are only reference values; and because the stepper motor is powered by a pulse method, the power supply voltage is its highest voltage, not the average voltage. The incoming motor can work beyond its rated value range. But the selection should not violate the rated value too far. (7) When the offline signal FREE is low, the current output from the driver to the motor is blocked, and the motor rotor is in a free state (offline state). In some automation equipment, if the drive is required to directly roll the motor shaft (manual method), the FREE signal can be set low to make the motor offline for manual operation or adjustment. After the manual is completed, the FREE signal is set high again to continue automatic control. (8) Use a simple method to adjust the rolling direction of the two-phase stepping motor after power-on, just swap the A+ and A- (or B+ and B-) of the motor and the drive wiring. (9) The power supply current is generally determined based on the output phase current I of the driver. If a linear power supply is used, the power supply current can generally be 1.1 to 1.3 times I; if a switching power supply is used, the power supply current can generally be 1.5 to 2.0 times I. (10) The stepper motor can work normally at low speed, but if it is higher than a certain frequency, it cannot be started, accompanied by howling. The stepper motor has a technical parameter: no-load starting frequency, that is, the pulse frequency that the stepping motor can normally start under no-load conditions. If the pulse frequency is higher than this value, the motor cannot start normally and may lose step or stall. Under load, the starting frequency should be lower. If you want the motor to reach high-speed rolling, the pulse frequency should be accelerated, that is, the starting frequency is lower, and then it must be accelerated to the desired high frequency (the motor speed increases from low speed to high speed). (11) The four-phase hybrid stepping motor is generally driven by a two-phase stepping driver. Therefore, the series connection or parallel connection method can be used to connect the four-phase motor into two phases when connecting. The series connection method is generally used in the occasions where the motor speed is low. The driver output current required at the moment is 0.7 times of the motor phase current, so the motor heat is small; the parallel connection method is generally used in the occasions where the motor speed is high (also called high-speed connection) ), the required driver output current is 1.4 times the motor phase current, so the stepper motor generates more heat. (12) The power supply voltage of the hybrid stepping motor driver is generally a wide range (for example, the power supply voltage of IM483 is 12~48VDC), and the power supply voltage is generally selected according to the operating speed and response requirements of the motor. If the motor has a high operating speed or a faster response to the requirements, the voltage value is also high, but note that the ripple of the power supply voltage cannot exceed the maximum input voltage of the drive, otherwise the drive may be damaged.

How to realize the forward and reverse rotation of the stepper motor? What is the stepper motor direction signal? The direction current signal DIR is used to control the rotation direction of the stepper motor. When this end is high, the motor turns one direction; when this end is low, the motor turns another. Motor commutation must be performed after the motor stops, and the commutation signal must be sent after the last CP pulse in the previous direction and before the first CP pulse in the next direction. When your controller (host computer) sends out a double pulse (that is, positive and negative pulse) or the amplitude of the pulse signal does not match, you need to use our signal module to convert it to a 5v single pulse (pulse: in the plus direction). 1. The DIP switch of the single-pulse signal module input should be set to the single-pulse position. The motor rotates when there is a pulse output. Changing the high and low levels of the direction signal can change the direction of rotation of the motor. For specific timing, please refer to the signal module manual. 2. The input is double pulse. The DIP switch of the signal module should be set to the · double pulse: middle · position. When a positive pulse is sent; in the middle, the motor rotates forward; when a negative pulse is sent, the motor reverses. The positive and negative pulses cannot be given at the same time. For the specific timing, please refer to the signal module manual. How should the stepping motor run in the opposite direction to the requirement, how should it be adjusted? The technical engineer of Shanshe Electric recommends the following two methods: One method is to change the control The direction signal of the system. The other method is to change the direction by adjusting the wiring of the stepper motor. The specific method is as follows: For a two-phase motor, only one phase of the motor wire exchange can be connected to the stepper motor driver, such as A+ and A- exchange . For a three-phase motor, one of the motor wires cannot be exchanged, but the two phases should be exchanged sequentially, such as swapping A+ and B+, and A- and B-. The reason why the stepper motor rotates in one direction: 1. It may be that the direction signal is too weak, or the polarity of the wiring is wrong, or the signal voltage is too high and it burns the direction current limiting resistor. 2, the pulse mode does not match, the signal is pulse/direction, and the stepper motor driver must be set to this mode; if the signal is CW/CCW (double pulse mode. The drive must be set to this mode; if the signal is CW/CCW (double pulse mode), the drive must also be in this mode, otherwise the motor will only run in one direction. How can the stepper motor rotate? The stepping motor needs to be energized correctly to rotate; the current way is mostly: the controller sends pulses to the stepping motor driver, the driver amplifies the pulse distribution to the stepping motor, and the stepping motor starts to rotate. The correlation between stepper motor speed and load: ①, if the load torque is too large, the motor cannot drive the load, and there is a serious loss of step, then the speed of the motor is related to the load. Of course, this is not the normal working state of the stepper motor; ②, the torque of the stepping motor decreases with the increase of the speed; ③. The current of the stepper motor is related to the load. The size of the current determines the size of the torque. When selecting a stepper motor, one of the parameters is the current; ④. Under the normal working condition of the motor, as long as the pulse frequency remains unchanged, the stepper motor can be regarded as a constant speed output; ⑤. As long as the load torque is not greater than the holding torque of the stepper motor, its speed has nothing to do with the load. At this time, the speed of the stepper motor is determined by the pulse frequency. The higher the frequency, the higher the speed.

When there is a problem with the motor, we should check and solve the fault in time. The premise is that we have a certain understanding of the possible problems of the motor. Today, I will mainly introduce you to the noise treatment methods of the brushless DC motor. Please read it carefully. 1. Vibration reduction and blocking measures When the reducer is installed, try to avoid resonance between the body, the foundation support and the connecting parts, resulting in noise. The energy-saving DC brushless reduction motor often has one or several inside the reduction motor The gear resonates in certain speed ranges. Except for design reasons, it is directly related to the location of the resonance that has not been tested during installation and the corresponding damping or blocking measures are taken. Some require low transmission noise and vibration reduction The machine should use high toughness, high damping base materials to reduce noise and vibration. 2. Damage to the transmission parts. During installation, improper operation damages the transmission parts, resulting in inaccurate or unstable movement of the system; damage to high-speed moving parts causes oil film vibration; artificial imbalance of moving parts; vibration and noise are caused. The reason must be noted and avoided as much as possible during the installation process. Damaged parts that cannot be repaired must be replaced to ensure that the system obtains a stable noise level. 3. The parts of the DC brushless geared motor are loose due to the loosening of individual parts (such as bearing pre-tensioning mechanism, shafting positioning mechanism, etc.) during installation, resulting in inaccurate positioning of the system, abnormal position engagement, and shafting Movement will cause vibration and noise. This series needs to start from the design structure, try to ensure the stability of the connection of each mechanism, and adopt a variety of connection methods. Among them, the geometric accuracy adjustment of the parts and components did not meet the requirements of the standard when the geometric accuracy was installed, which caused the brushless DC motor parts to resonate and generate noise. This should improve the installation process, increase tooling, and ensure the overall quality of the assembly personnel Direct relationship.

Toy motors are generally divided into five categories: brushless motors, brush motors, stepper motors, gear motors and coreless motors. Brushless motors are relatively expensive, so cheaper toys generally do not use brushless motors. In addition, brushless motors also have an essential feature, that is, they must have an electronic circuit board, that is, a chip, so everyone sees a motor with a chip. Generally brushless motors. Brush motors are the most common and inexpensive. Generally, cheaper toys use brush motors. Brush motors also have an essential feature, that is, there are two brush contacts on its back cover. A brush contact is used to conduct electricity for the brushed motor. The most direct feature of a stepper motor is that it rotates one after another, which is not continuous, so everyone sees that a motor that rotates after one meal is a stepper motor. Geared motors generally rotate slowly and rotate continuously. Everyone sees toy motors that turn slowly and coherently. Generally, geared motors are divided into brushed geared motors, brushless geared motors, and coreless geared motors. The coreless motor has neither a rear cover with brush contacts nor an electronic circuit board, and the rotation is continuous, so it is easier for everyone to identify.

The previous blinds were manual, and you need to pull back and forth to control its switch every time you use it. A little bit of force may damage the blinds. Since the emergence of electric blinds, these troubles have been solved, and the most important thing in electric blinds is electric The shutters are motorized. Electric shutter motor_electric window opener motor manufacturer-wanzhida motor The driving system of electric blinds is composed of electric blinds motor, rope reel and a mechanical stopper. The electric blinds motor must drive the movement of the whole window blinds, it needs to provide a suitable power to the blinds. If the power is too large, it may be The blinds and the entire system cause damage and shorten the service life of electric blinds; if the power of the electric blinds motor is too small, it will not be able to drive the motion of the blinds, which cannot achieve the intended purpose, so the choice of the electric blinds motor is extremely important. At present, the shutters used in homes or hotels on the market are mainly DC electric shutter motors. The DC electric shutter motors have the characteristics of small size, low vibration, low noise, and low power consumption. Shenzhen Zhengde Intelligent Control Co., Ltd. specializes in the research and development and production of modern smart door and window drive motors. The main products are electric blinds motors, electric window openers and electric sunshade motors. At the same time, Zhengde Intelligent Control provides customized development services, such as output power, output speed, voltage, diameter specifications, gearbox transmission type, reduction ratio, output torque and other technical parameters are customized development, Zhengde Intelligent Control provides one-stop customized development solutions service.

The working principle of the educational robot motor is to use the principle of electromagnetics to convert electrical energy into mechanical energy and convert electrical pulse signals into an open-loop control stepping motor that uses angular displacement or linear displacement. Stepping motors are widely used in industries, aerospace, robotics, precision measurement and other fields, such as photoelectric theodolites for tracking satellites, military instruments, communications and radars. In the case of non-overload, the rotational speed and stop position of the educational robot motor only depend on the frequency and pulse number of the pulse signal, and are not affected by load changes. When the stepper driver receives a pulse signal, it drives to rotate a fixed angle in the set direction, called "step angle", and its rotation runs step by step at a fixed angle. The educational robot motor can control the angular displacement by controlling the number of pulses, so as to achieve the purpose of accurate positioning; at the same time, it can control the speed and acceleration of the motor rotation by controlling the pulse frequency to achieve the purpose of speed regulation. Generally, the rotor of an educational robot motor is a permanent magnet. When the current flows through the stator winding, the stator winding generates a vector magnetic field. The magnetic field drives the rotor to rotate by an angle, so that the pair of magnetic field directions of the rotor are consistent with the magnetic field directions of the stator. When the vector magnetic field of the stator rotates by an angle, the rotor also rotates by an angle with the magnetic field. Each time an electrical pulse is input, the educational robot motor rotates one step forward. The angular displacement output is proportional to the number of input pulses, and the speed is proportional to the pulse frequency. Changing the sequence of winding energization, the motor will reverse, so the number of pulses, frequency and the energization sequence of each phase winding of the motor can be controlled to control the rotation of the stepper motor.

To understand the "subdivision" of the stepper motor driver, we must first clarify the concept of the "step angle" of the stepper motor. The step angle is the mechanical viewpoint that the rotor has rotated about a pulse signal without a reduction gear. The step angle of the stepping motor indicates the point of view that the stepping motor scrolls every time the control system sends a pulse signal. In other words, the point of view at which the rotor rotates for each input pulse signal is called the pitch angle. It can also be described like this: every time the stator control winding changes the energization method, it is called a beat. The mechanical viewpoint at which the rotor turns at each beat is called the step angle, which is usually expressed by θs. The common ones are 3°/1.5°, 3.6°/1.8°. For example, for a stepping motor (small motor) with a step angle of 1.8 degrees, the number of pulses used for one revolution is n=360/1.8=200 pulses. The error of the step angle will not accumulate for a long time, and only corresponds to the number of input pulse signals. It can form an open-loop control system with a simpler structure and a certain degree of accuracy, and it can also form a closed-loop system when higher precision is required. After giving an example to clarify the step angle, we can understand this concept more clearly. For example, the value given by the stepper motor is 7.5°/15° (indicating that it is 7.5° for half-step operation and 15° for full-step operation), this step angle can be called the "motor inherent step angle", it It is not necessarily the actual step angle of the stepper motor in actual operation, the actual step angle is related to the driver. What is the breakdown of the drive? In short, the number of subdivisions means that the true step angle when the stepper motor is running is a fraction of the inherent step angle (full step). It can be seen from the following table: when the drive is operating in 10 subdivision conditions, its step angle is only one tenth of the "motor inherent step angle", that is to say: when the drive is operating in a full step without subdivision When the control system sends out a step pulse, the motor rolls 1.8°; when the subdivision driver is used in the 10 subdivision condition, the motor only rolls 0.18°. This is the basic concept of subdivision. A more accurate description of the subdivision characteristics of the drive is the number of running beats, which refers to the number of pulses required for each tooth pitch when the stepper motor is running. A certain motor has 50 teeth. If the number of running beats is set to 160, then a total of 50×160=8000 steps are required for one revolution of the stepper motor; the corresponding step angle is 360°÷8000=0.045°. Please note that if the number of running beats is set to 30, the corresponding subdivision number according to the above table is 7.5, not an integer. The subdivision function is completely generated by the driver by accurately controlling the phase current of the stepper motor, and has nothing to do with the stepper motor.

Stepping motors can play a role in practical applications are realized by its components, and the three components that play the greatest role are the rotor, the iron core, and the stator. These three components cooperate and coordinate to complete the relevant functions of the motor. . 1, rotor There are two types of rotors, salient pole type and hidden pole type. The salient pole type air gap is not uniform, while the core of the hidden pole type rotor is forged from a single piece of steel. The surface is round and the air gap More uniform. 2.Iron core The iron core is also one of the very important components of the Zhengde stepping motor. It is made of silicon steel sheets. When the motor runs stably, the main magnetic flux in the iron core in the rotor remains unchanged, so that no magnetic flux will be caused. Hysteresis losses and eddy currents. 3, stator The stator is one of the very important structural components of a stepper motor, and its structure and winding form are basically similar to those of induction motors. The above content introduces several important components in the stepper motor, and more maintenance is required when it is applied to ensure its long-term use and good use effect.

This article is mainly about the introduction of the brushless DC motor, and focuses on the reasons for the excessive vibration of the brushless DC motor at no-load starting. Brushless DC motor The brushless DC motor is composed of a motor body and a driver, and is a typical mechatronic product. Because the brushless DC motor works in a self-controlled manner, it will not add a starting winding on the rotor like a synchronous motor driven by a heavy load under variable frequency speed regulation, nor will it vibrate and lose step when the load changes suddenly. For the permanent magnets of small and medium-capacity brushless DC motors, the rare earth neodymium iron boron (Nd-Fe-B) materials with high magnetic energy levels are now mostly used. Therefore, the volume of the rare earth permanent magnet brushless motor is one size smaller than the three-phase asynchronous motor of the same capacity. Principle of operation Brushless DC motors use semiconductor switching equipment to complete electronic commutation, that is, electronic switching equipment is used to replace traditional touch commutators and brushes. It has the advantages of low mechanical noise, no reversing sparks, and high reliability. It is widely used in high-level automated office equipment, electronic instruments, video recorders, and recording stands. The brushless DC motor consists of a permanent magnet rotor, a multi-pole winding stator, and an orientation sensor. The orientation sensor changes the current of the stator winding along a certain order according to the change of the rotor orientation (that is, detects the orientation of the rotor pole relative to the stator winding, and generates an orientation sensor signal at the determined orientation, which is processed by the signal conversion circuit To control the power switch circuit, switch the winding current according to a certain logical connection). The operating voltage of the stator winding is supplied by an electronic switch circuit controlled by the output of the orientation sensor. There are three types of orientation sensors: photoelectric, electromagnetic and magnetic sensitive. The brushless DC motor with magneto-sensitive azimuth sensor is selected, and its magneto-sensitive sensor materials (such as magneto-sensitive pole tube, magneto-sensitive diode, Hall element, magneto-sensitive resistor or special integrated circuit, etc.) are installed on the stator assembly. To detect the change of the magnetic field generated when the permanent magnet and the rotor rotate. The brushless DC motor with photoelectric azimuth sensor is selected. The stator assembly is equipped with photoelectric sensor material in a certain direction, the rotor is equipped with a light shield, and the light source is a light-emitting diode or a small bulb. When the rotor rotates, due to the effect of the shading plate, the photosensitive element equipment on the stator will generate pulse signals intermittently at a certain frequency. The brushless DC motor with electromagnetic orientation sensor is equipped with electromagnetic sensor components (such as coupling transformer, LC resonance circuit, proximity switch, etc.) on the stator assembly. When the permanent magnet rotor orientation changes, the electromagnetic effect will cause the electromagnetic sensor A high-frequency modulation signal occurs (its amplitude changes with the rotor position). Structure analysis In terms of structure, brushless DC motors and brushed DC motors have similarities. There are also rotors and stators, but they are opposite to the structure of brushed motors. The rotors of brushed motors are coil windings connected to the power output shaft, and the stator is permanent. Magnetic steel: The rotor of the brushless DC motor is a permanent magnet, which is connected to the output shaft together with the casing. The stator is a winding coil. The brushed DC motor is removed to replace the commutation brush for changing the electromagnetic field, so it is called Brushless DC Motor (Brushless DC Motor), then there is a problem now. Without the change of the electromagnetic field, how to make the brushless DC motor roll? In short, relying on changing the alternating frequency and waveform of the current wave input to the stator coil of the brushless DC motor, a magnetic field rotating around the motor axis is formed around the winding coil, and this magnetic field drives the permanent magnet on the rotor to roll. , The motor starts to rotate. The function of the motor is related to the number of magnets, the strength of the magnetic steel flux, the size of the motor input voltage and other factors. It is also closely related to the control function of the brushless DC motor, because the input is DC, current The electronic speed governor is required to turn it into a 3-phase communication circuit, and it is also required to receive the control signal from the remote control receiver to control the speed of the motor to satisfy the requirements of the model application. In general, the structure of the brushless DC motor is relatively simple. The actual function of the brushless DC motor is still the brushless electronic governor. A good electronic governor requires microcontroller control program design, circuit design, and messy processing technology. Wait for the overall control of the process, so the price is much higher than the brushed DC motor. Reasons for excessive vibration of brushless DC motor at no-load starting On the other hand, the water resistance between the moving plate and the case heats up due to the passing current, and under the effect of the negative temperature characteristics of the water resistance, the resistance will gradually decrease. Summarizing the effects of the above two aspects, the motor is started with a constant torque and a constant current. What is the reason for the excessive vibration of the brushless DC motor at no-load starting? The brushless automatic control motor soft starter is to directly install the starting resistance on the shaft of the motor, and use the centrifugal force generated when the motor rotates as the power to control the size of the resistance to reduce the motor starting current, increase the starting torque, and make the winding asynchronous The motor completes the brushless automatic control equipment. It is mainly composed of a casing, electrolyte, moving plate, tension spring, terminal, safety valve, exhaust valve, etc. The reason for the excessive vibration of the brushless DC motor at no-load starting is about the above conditions. Common motor faults and solutions When the motor is working or malfunctioning, the four methods of watching, hearing, smelling and touching can be used to prevent and troubleshoot in time to ensure the safe operation of the motor. one look Investigate whether there are abnormalities in the working process of the motor, which are mainly manifested in the following situations. 1. If there are discoloration, burn marks and smoke trails at the touch points and joints in the motor, it means that there may be some overheating, poor touch at the conductor joints or burnt windings. 2. If the motor vibrates violently, it may be that the transmission equipment is jammed, the motor is not properly fixed, and the foot bolts are loose. 3. The motor repair net works normally, but when it suddenly stops, you will see sparks from the loose wiring; the fuse is blown or a part is stuck. 4. When the motor is severely overloaded or working under phase loss, the speed will slow down and there will be a heavier buzzing sound. 5. When the stator winding is short-circuited, you may see smoke from the motor. Second, touch Touching the temperature of some parts of the motor can also determine the cause of the fault. To ensure safety, use the back of your hand to touch the motor housing and the surrounding parts of the bearing when touching with your hands. If the temperature is abnormal, the reasons may be as follows. 1. Start or brake frequently. 2. If the temperature around the bearing is too high, it may be caused by damage to the bearing or lack of oil. 3. Short circuit between stator winding turns or unbalanced three-phase current. 4. Poor ventilation. Such as the falling of the electric fan and the obstruction of the ventilation duct. 5. Overload. The current is too large and the stator winding is overheated. Three, smell After smelling the smell of the motor, it can also be judged and prepared for failure. If there is a special paint smell, it indicates that the internal temperature of the motor is too high; if there is a heavy paste or burnt smell, it may be that the insulation repair net has been broken down or the winding has been burned. Four, listen When the motor is working normally, it should declare a uniform and light hum, no noise and special sound. If the noise is declared to be too large, including electromagnetic noise, bearing noise, ventilation noise, mechanical conflict sound, etc., it may be a precursor to a failure or a failure phenomenon. 1. If the transmission organization and the transmission organization announce that the sound is continuous rather than fluctuating, it can be dealt with in the following situations. (1) The uneven knocking sound is caused by the wind blade knocking against the fan cover. (2) Periodic buzzing sound is caused by the loosening between the coupling or the pulley and the shaft and the wear of the key or keyway. (3) Periodic snapping noise is caused by uneven belt joints. 2. Regarding bearing noise, you should always monitor the motor while working. The monitoring method is: press one end of the screwdriver against the bearing equipment part and the other end close to the ear, you can hear the sound of the bearing. If the bearing is working normally, its sound will be successive and small rustling, and there will be no high and low changes and metal clashes. If the following sounds are present, it is abnormal. (1) If there is a clicking sound or a creaking sound, it is the sound produced by the irregular movement of the balls in the bearing, which is caused by the damage of the balls in the bearing or the drying of the grease after the motor is not used for a long time. (2) If there is a chirping sound, which is the sound announced when the ball is rolling, it is usually caused by the drying of the grease or lack of oil, and an appropriate amount of grease can be added. (3) There is a squeaking sound when the bearing is working. This is the sound of metal conflict, which is generally caused by the lack of oil in the bearing. The bearing should be disassembled and added with an appropriate amount of grease. 3. Regarding electromagnetic noise, if the motor announces a high, low and heavy sound, the reasons may be as follows. (1) The iron core is loose. When the motor is working, due to vibration, the fixing bolts of the iron core are loosened and the iron core silicon steel sheet is loosened, which generates noise. (2) The three-phase current is unbalanced. This is because the three-phase windings are grounded incorrectly, short-circuited, or poorly touched. If the sound is very annoying, it means that the motor is severely overloaded or the motor is working without phase. (3) The air gap between the stator and the rotor is not uniform. At this moment, the sound fluctuates and the interval between high and low frequencies does not change. This is caused by the wear of the bearing, which makes the stator and the rotor not concentric. Motor fault detection and troubleshooting methods 1. The no-load current of the motor is large The measurement method is as follows: Use the 20A gear of the multimeter to connect the red and black test leads of the multimeter in series to the power input of the controller. Turn on the power, record the maximum current value A1 of the multimeter at the moment when the motor is not rolling, and roll the handle to make the motor roll at high speed without load for more than 10 seconds, and the motor speed is stable. After that, start to investigate and record the maximum value of the multimeter at the moment A2. The no-load current of the motor = A2-A1. Refer to the table below for the maximum limit no-load current without failure of various motors: Motor mode extra voltage 24V extra voltage 36V Side hanging motor 2.2A1.8A High-speed brushed DC motor 1.7A1.0A Low speed brushed DC motor 1.0A 0.6A High speed brushless DC motor 1.7A1.0A Low speed brushless DC motor 1.0A 0.6A When the no-load current of the motor is greater than the limit data in the table, it indicates that the motor is malfunctioning. The reasons for the large no-load current of the motor are: 1) Demagnetization of magnetic steel. 2) The coil is partially short-circuited. 3) The internal mechanical conflict of the motor is large. We continue to do related tests and check items, and we can further identify the cause of the failure or the location of the failure. 2. Phase loss of brushless DC motor The lack of phase of the brushless motor is generally caused by the damage of the hall element of the brushless motor. We can measure the resistance of the output lead of the hall element relative to the hall ground wire and the relative hall power lead, and use the comparison method to determine which Hall element is. The ear element is malfunctioning. To ensure the accuracy of the motor commutation orientation, it is generally recommended to replace all three Hall elements at the same time. Before replacing the Hall element, it is necessary to find out whether the phase algebraic angle of the motor is 120 degrees or 60 degrees. Generally, the three Hall elements of a 60-degree phase angle motor are placed in parallel. In the 120-degree phase angle motor, one hall element in the center of the three hall elements is placed in an orientation that is turned 180 degrees. 3. Motor heats up Use a non-touch infrared thermometer, or the temperature measurement gear of a multimeter (multimeter with temperature measurement), when the temperature of the motor end cover exceeds the ambient temperature by more than 30℃, it indicates that the temperature rise of the motor has exceeded the normal range. The temperature rise of the motor is below 25°C. The direct cause of the motor heating is caused by the large current. Motor current i, motor input electromotive force E1, motor rotation induced electromotive force (also known as back electromotive force) E2, and the relationship between the motor coil resistance R is: i=(E1-E2)÷R The increase in i indicates that R becomes smaller or E2 is reduced. The decrease of R is generally caused by a short circuit or an open circuit of the coil. The reduction of E2 is generally caused by the demagnetization of the magnetic steel or by the short circuit or open circuit of the coil. In the practice of repairing the entire vehicle of an electric vehicle, to deal with the fault of the motor heating, it is generally to replace the motor. 4. The no-load/load speed ratio of the motor is greater than 1.5 The measurement method is as follows: turn on the power, roll the handle, make the motor roll at high speed and no-load for more than 10 seconds, and the motor speed is stable. In the future, use a hand-held speed/speed meter to measure the no-load maximum speed N1 of the motor at the moment. Under the standard load, Travel more than 200m intervals, start to measure the maximum load speed N2 of the motor. No-load/load speed ratio=N2÷N1 When the no-load/load speed ratio of the motor is greater than 1.5, it indicates that the magnet demagnetization of the motor is now adequately strong, and the entire set of magnets in the motor should be replaced. Generally, the entire motor is replaced in the actual repair process of electric vehicles. 5. There are mechanical bumps or mechanical noise inside the motor when it is working Regardless of whether the high-speed motor is still a low-speed motor, there should be no mechanical bumps or irregular mechanical noise when the load is working. Analysis of common faults of motors and countermeasures Low-voltage three-phase communication motors (hereinafter referred to as motors) have the advantages of simple structure, low price, and convenient repair. Therefore, it is widely used in the driving equipment of industrial and agricultural machinery and equipment, and it is the most widely used kind of all motors. Nevertheless, the motor will inevitably have various failures in actual work. Below, analyze the causes of common motor faults and the countermeasures adopted for the reference of colleagues. 1. The motor speed becomes lower 1. The connection method of the stator winding is wrong, please check and correct the connection method. 2. If the rotor guide bar is cracked or desoldered, check and repair the broken bar. 3. The power supply voltage is too low. Check and find out the reason. 2. When the motor is working, the ammeter pointer swings back and forth The cause of this failure is likely to be an open circuit of the rotor guide bar. 3. Three-phase current imbalance is formed during work 1. One parallel branch or several parallel branches of a group of three-phase windings is open, resulting in unequal three-phase impedance. 2. One-phase open circuit or one-phase fuse blown in the three-phase winding causes phase loss work. 3. The beginning and end of a phase in the three-phase stator winding are wrong, but the fuse is not blown. 4. The three-phase power supply voltage is severely unbalanced (that is, not equal). Such as poor touch of switch contacts. 5. There is a partial short circuit between winding turns or phases, and the fuse is not broken. 4. Excessive vibration 1. The fan is unbalanced; 2. The transmission pulley is unbalanced, so the static balance should be checked. 3. The driven machine loses its dynamic balance. 4. The iron core is deformed or loose. 5. The rotor bar is cracked, causing the load current to vibrate from time to time. 6. The coupling device is incorrect or loose. 7. The shaft is twisted. The shaft should be replaced, or the car straight insert sleeve (hot sleeve). 8. Part of the stator winding is faulty, and the rotating magnetic field is unbalanced, causing vibration. 9. The bearing clearance is too large due to wear; 10. The bottom of the equipment is uneven or unstable. The equipment should be re-installed and fixed smoothly. 11. If the rotor of the motor is unbalanced (such as the weight screw on the rotor is dropped), the dynamic balance should be checked. 5. Abnormal noise 1. The first and last ends of the stator winding are wired incorrectly, there is a low roar, and the speed drops. 2. When the wind blade hits the shell or has debris, it will announce the impact sound. The wind blades should be calibrated and the debris around the wind blades should be removed. 3. When the bearing is severely short of oil, a "sizzling" sound can be heard from the bearing chamber. The bearings should be cleaned and new oil should be added. 4. The motor is working under phase loss and the roar is very loud. It can be switched off and on again to see if it can start normally again. If it cannot be started, there may be a phase open circuit.

Stepper motor products are widely used in smart home appliances, sanitary ware, security equipment, office equipment, stage lighting, textile machinery, robots, packaging machinery and other automation control fields that require precise positioning, automatic aiming and automatic recording. Now that we have entered the era of intelligence, mobile phones have become an indispensable thing for people, ranging from old to small, with almost one hand. This has also contributed to its more and more powerful functions. At present, high-end smart phones basically have wireless charging functions, and cars are becoming more and more popular, especially private cars. When smart phones have the opportunity to use private cars , Only the car wireless charging stand is more equipped. At present, there are two main types of wireless charging brackets on the market, one is a gravity bracket, and the other is an infrared touch sensor automatic telescopic bracket. In contrast, the infrared touch-sensing automatic telescopic stand is more high-end and firm. After the power is turned on, when the mobile phone is close to the sensor, the clamping devices on both sides of the stand will automatically open. After the mobile phone is put on, the clamping device will open again. It will automatically shrink to fix the phone. Here, thanks to the deceleration stepper motor inside. By disassembling the car wireless charger, we can find that the motor that drives the bracket automatically retracts and looks very mini, which is a control component, also called a deceleration stepper motor. It is an applied miniature geared motor with the characteristics of low noise, long life, low power consumption, anti-interference and high temperature resistance. In order to better meet market demand, it is usually customized according to customer requirements. Motor voltage, speed, torque, gearbox reduction ratio, step angle, resistance, etc. are all customized according to customer application requirements.

After adopting the closed-loop technology, the closed-loop stepper motor provides users with excellent accuracy and efficiency, which can not only achieve the performance of a servo motor, but also has the low price advantage of a stepper motor. Lower-cost stepper motors are gradually penetrating into the application fields originally dominated by high-cost servo motors. The comparison of stepping motor and servo motor According to the traditional concept, the performance of the servo control system is better in applications that require speeds exceeding 800rpm and high dynamic response. Stepper motors are more suitable for applications with low to medium acceleration, low speed, and high holding torque. The detailed analysis of stepper motor and servo motor is as follows: 1. Simplicity and cost Stepping motors are not only cheaper than servo motors, but also easier to debug and maintain. The stepper motor is stable at rest and can maintain its position (even with dynamic loads). However, if certain applications have higher performance requirements, more expensive and more complex servo motors must be used. 2, positioning In applications that need to know the exact position of the machine at any time, there are important differences between stepper motors and servo motors. In an open-loop motion application controlled by a stepper motor, the control system believes that the motor is always in the correct motion state. However, after encountering a problem, such as a motor stall due to a stuck component, the controller cannot understand the actual position of the machine, resulting in a loss of position. The closed-loop system of the servo motor itself has an advantage: if it gets stuck by an object, it will be detected immediately. The machine will stop operating and never lose its position. 3, structure The stepping motor rotates in a step-by-step manner, using a magnetic coil to gradually pull a magnet from one position to the next. To make the motor move 100 positions in any direction, the circuit needs to perform 100 steps on the motor. Stepper motors use pulses to achieve incremental motion, which can achieve precise positioning without using any feedback sensors. The movement method of the servo motor is different. It connects a position sensor-an encoder-to the magnetic rotor to continuously detect the exact position of the motor. The servo will monitor the difference between the actual motor position and the commanded position, and adjust the current accordingly. This closed-loop system can keep the motor in the correct state of motion. 4. Heat and energy consumption The open loop stepper motor uses a fixed current and emits a lot of heat. The closed-loop control only provides the current required by the speed loop, thus avoiding the problem of motor heating. Servo control system is most suitable for high-speed applications involving dynamic load changes, such as robotic arms. Stepping control systems are more suitable for applications that require low to medium acceleration and high holding torque, such as 3D printers, conveyor belts, and countershafts. Because the cost of stepping motors is lower, after use, the cost of the automation system can be reduced. If the motion control system needs to use the characteristics of servo motors, it must prove that these higher-cost motors are worth the money. Driven by the progress of closed-loop technology, stepper motors can penetrate into the high-performance and high-speed application fields that were formerly servo motors. 5, speed and torque The performance difference between stepper motor and servo motor stems from their different motor design schemes. The number of poles of a stepper motor is much more than that of a servo motor. Therefore, a stepper motor rotates a full circle, and the required winding current exchange times are much more, which causes its torque to drop rapidly as the speed increases. In addition, if the maximum torque is reached, the stepper motor may lose the speed synchronization function. For these reasons, in most high-speed applications, servo motors are the preferred solution. In contrast, a stepper motor with more poles has an advantage at low speeds, because a stepper motor has a torque advantage compared to a servo motor of the same size. As the speed increases, the torque of the stepper motor will decrease. How does the advantage of closed-loop servo technology apply to stepper motors? Can we realize the cost advantages of stepper motors while achieving performance similar to that of servo motors? By combining closed-loop control technology, stepper motors will become a low-cost comprehensive product with the advantages of both servo and stepper motors. Because closed-loop stepper motors can significantly improve performance and energy efficiency, they can replace more expensive servo motors in more and more high-standard applications. Next, we take Zhengde intelligent control stepper motor with embedded closed-loop control function as an example to analyze the performance and advantages and disadvantages of stepper motor using closed-loop technology. The stepper motor of Zhengde intelligent control products adopting closed-loop control after integrated electronic control is equivalent to a two-phase brushless DC motor, which can perform position loop control, speed loop control, DQ control, and other algorithms. A single-turn absolute encoder is used to achieve closed-loop commutation to ensure that the best torque can be achieved at any speed. Low energy consumption and keep cool MAINTEX stepping motor has high energy efficiency. Unlike the open loop stepper motor that always operates in accordance with the full current command, which will cause heating and noise problems, the current of Zhengde Intelligent Control will change according to the actual situation of the movement, such as during acceleration and deceleration. Similar to servos, at any moment, the current consumed by these stepper motors is proportional to the actual torque required. Because the motor and integrated electronic control board run at a lower temperature, Zhengde intelligent control stepping motors can achieve higher peak torque similar to servo motors. Even at high speeds, Zhengde intelligent control stepping motors require less current. Exactly match performance requirements In order to ensure that there is enough torque to overcome interference and avoid out-of-step, open-loop stepper motors usually have to ensure that the torque is at least 40% higher than the value required by the application. The closed-loop Zhengde intelligent control stepper motor does not have this problem. When these stepper motors reach a stall state due to overload, they will continue to maintain the load state without losing torque. After the overload condition is eliminated, they will continue to run. At any specified speed, the maximum torque can be guaranteed, and the position sensor can be used to ensure that it will not lose step. Therefore, the specifications of the closed-loop stepper motor can accurately match the torque requirements of the relevant application without an additional 40% margin. For an open-loop stepper motor, it is difficult to meet the high transient torque demand because of the risk of losing step. Zhengde intelligent control closed-loop stepper motor can achieve fast acceleration, lower running noise, and has less resonance than traditional stepper motors. They can operate at higher bandwidths and achieve excellent performance. Closed-loop stepper motors have changed the performance-cost ratio in many motion control applications. Because of its excellent precision and energy efficiency, Zhengde intelligent control stepping motors can be used in the fields that used to be more expensive servo motors. Zhengde intelligent control closed-loop progressive motor can replace high-cost servo motors with low-cost stepper motors.

With the continuous development of the electrical machinery industry, the extension and the interior of electrical machinery products have been continuously expanded. Electrical machinery products are widely used in various fields such as papermaking, municipal administration, water conservancy, shipbuilding, port handling, metallurgy, electric power, petrochemical, coal, mining, building materials and so on. As a device that converts electrical energy into mechanical energy, motors are widely used in various fields such as papermaking, municipal administration, water conservancy, shipbuilding, ports, food processing machinery, metallurgy, electric power, petrochemicals, coal, mining, building materials and so on. The versatility of motors gradually develops towards specificity, breaking the situation that the same motors were used for different load types and different applications in the past. After more than 40 years of development in my country`s motor industry, especially the rapid development of more than 20 years of reform and opening up, the small motor manufacturing industry has begun to develop in the direction of standardization, scale and automation, while the large and medium-sized motor manufacturing industry has continued to increase in single-machine capacity. The direction of specialization, diversification and customization has made great progress. According to the "2014-2018 China Motor Manufacturing Industry Market Demand and Investment Planning Analysis Report" released by the Qianzhan Industrial Research Institute, the rapid development of new energy has driven the rapid growth of the motor industry, and my country's motor industry has broad development prospects. At the same time, high efficiency and energy saving are also the development trend of the entire industry. The following editor will make a brief analysis of the development trend of the small motor manufacturing industry. The small motor manufacturing industry will develop along three major trends. 1. Personalization, specialization, and specialization With the continuous development of the electrical machinery industry, the extension and interior of electrical machinery products have been continuously expanded. Electrical machinery products are widely used in various fields such as papermaking, municipal administration, water conservancy, shipbuilding, ports, metallurgy, electric power, petrochemical, coal, mining, building materials, loading and unloading. The versatility of motors has gradually developed in the direction of specificity, breaking the situation that the same motors were used in different load types and different applications in the past, and motors are developing in the direction of individualization, specificity and particularity. Many domestic enterprises are also transforming into specialized enterprises, such as coal mine electrical machinery factory, explosion-proof electrical machinery factory, micro-special electrical machinery factory, etc. Whether the enterprise has the ability to adapt to non-standard customization is an important aspect of measuring the future development potential of an enterprise. 2. The single-machine capacity of the product continues to increase With the gradual increase in the scale of modern industrial output, the supporting production equipment is also developing in the direction of large-scale, integrated, and large-scale. The power of the motor that drives the large-scale machinery and equipment has also become larger and larger. , High voltage level, high performance motors have become the most important direction. Regarding all kinds of large AC and DC motors for transmission in railway traction, rail transit, ship power, drainage and irrigation pumps, rolling mills, power station auxiliary equipment, blast furnace fans, etc., the capacity of single machines has been expanding, and the variety has also been increasing, which has also promoted the production of motors. Enterprises have moved closer to the high-voltage large and medium-sized motor industry to enhance their competitiveness. 3. Resources gather to advantageous companies The level of technology determines the level of profit. The number of competitors from the motor industry as a whole, the average profit level is spread in a U-shape, and the number of competitors is spread in an inverted U-shape. At present, the motor industry has a high degree of marketization, with a large number of motor companies, and the entire industry is in a process of integration and optimization. Micro motors and large motors (including some special motors) are at the highest end of the U-shaped curve due to high technical difficulty, large initial investment, and high technical thresholds, with a higher average profit level and fewer competitors; small power motors , Small and medium-sized motors are at the center of the entire U-shaped curve, with a large number of competitors and a low average profit level.

MAINTEX brushless DC motors are energy-saving and environmentally friendly, and have a longer life. Variable frequency motors are the general term for motors driven by frequency converters. With the rapid development of frequency conversion speed regulation technology, various high-voltage frequency converters continue to appear, playing a huge role in energy saving in power plants. In fact, the motor planned for the frequency converter is called a variable frequency motor; the motor can achieve different speeds and torques under the drive of the frequency converter to meet the needs of load changes. The general frequency conversion motor is derived from the traditional squirrel cage motor; the traditional motor is generally changed from a self-cooling fan to an independent fan, and the corona resistance of the motor winding insulation is improved. In some occasions that do not require high motor output characteristics, such as low power, and when the operating frequency is near the additional frequency, it can be replaced by a general squirrel cage motor. The principle of variable frequency motor speed regulation: From the three-phase asynchronous motor speed formula: n=60f(1-s)/p, it can be seen that changing the power supply frequency f, the number of pole pairs p of the motor and the slip rate s can achieve the intention of changing the speed. From the perspective of the essence of speed regulation, different speed regulation methods are nothing more than changing the synchronous speed of the communication motor or not changing the synchronous speed. The speed regulation methods that do not change the synchronous speed are widely used in production machinery, such as the rotor series resistance speed regulation of the wound motor, the chopper speed regulation, the cascade speed regulation, and the use of electromagnetic slip clutches, fluid couplings, oil film clutches, etc. Speed regulation. There are multi-speed motors that change the number of stator pole pairs to change the synchronous speed, and the variable-frequency speed control of the stator voltage and frequency can be used to adjust the speed of the motor without commutation. From the perspective of energy consumption concept during speed regulation, there are two ways of high-efficiency speed regulation and low-efficiency speed regulation: high-efficiency speed regulation means that the slip rate is constant, so there is no slip loss, such as multi-speed motors and frequency conversion speed regulation. And the speed regulation method (such as cascade speed regulation, etc.) that can recover the slip loss. The speed control method with slip loss is inefficient speed control. For example, the rotor series resistance speed control method, the energy is lost in the rotor circuit; the electromagnetic clutch speed control method, the energy loss is in the clutch coil; the hydraulic coupling speed control method , The energy is lost in the oil of the fluid coupling. Generally speaking, the slip loss increases with the expansion of the speed control scale. If the speed control scale is not large, the energy loss is very small. Features of variable frequency motor: Electromagnetic planning For variable frequency motors, because the critical slip is inversely proportional to the power frequency, it can be started directly when the critical slip is close to 1. Therefore, overload capacity and starting function no longer need to be considered too much, but the key issue to be solved is how to improve The ability of the motor to adapt to non-sine wave power supplies and to ensure the service life of the motor. The method is generally as follows: 1) The main magnetic circuit of the variable frequency motor is generally planned to be under full condition. One is to consider that higher harmonics will make the magnetic circuit full, and the other is to appropriately increase the output voltage of the inverter in order to increase the output torque at low frequencies. 2) In order to suppress the higher harmonics in the current, the inductance of the motor needs to be appropriately added. However, the rotor slot leakage reactance is large, the skin effect is also large, and the copper loss of higher harmonics is also increased. Therefore, the size of the motor leakage reactance must take into account the rationality of impedance matching in the entire speed regulation scale. 3) Reduce the stator and rotor resistance as much as possible. Reducing the stator resistance can reduce the fundamental copper loss to compensate for the copper loss caused by higher harmonics. Structural planning In structural planning, the first thing to consider is the influence of non-sinusoidal power supply characteristics on the insulation structure, oscillation, noise, and cooling methods of the variable frequency motor. Generally, pay attention to the following issues: 1) For constant power variable frequency motors, when the speed exceeds 3000/min, special high-temperature-resistant grease should be selected to compensate for the temperature rise of the bearing. 2) To avoid shaft current, use bearing insulation for motors with a capacity exceeding 160KW. The main reason is that the asymmetry of the magnetic circuit is prone to occur, and the shaft current will also occur. When the currents generated by other high-frequency weights work together, the shaft current will be greatly increased, which will cause the bearing to be damaged by galvanic corrosion. Therefore, special insulation measures are generally adopted. . 3) Cooling method: generally use forced ventilation cooling, that is, the main motor cooling fan is driven by an independent motor. 4) For the vibration and noise of the motor, it is necessary to fully consider the rigidity of the motor components and the whole, and try to increase its natural frequency to avoid resonance with each force wave. 5) Insulation grade, generally F grade or higher, strengthen the insulation to ground and the insulation strength between turns, and especially consider the ability of insulation to withstand corona impact.

In September, when the school was busy, I had already left the school. Back then, I was able to find a direction in life by setting an example as a teacher. Now Yang Fan is on a voyage and he is grateful and loving. Teacher, you have worked hard, I wish you good health and happy Teacher's Day! "Lvyetang opened up the Wuhua, Passers-by pointed to Ling Gong's house. Make the peaches and plums all over the world, Why use more flowers in front of the hall. " The teacher is like a spring in the mountains Run everything silently; Return to the sea and never dry up. A thousand years of history of a great country, The loyal teacher keeps ten thousand volumes. Today, people also have good teachers, Draw a glorious China map again. Write a letterhead to the blackboard with chalk Like a spring silkworm nibbles a quiet poem Your appearance on the podium for many years Contracted the most beautiful picture in my memory Boring and jerky text He was given alive life in the eloquent explanation Difficult and difficult questions Was overcome and resolved one by one in the gentle and patient answers When the whole city fell into the silence of night Only the windows of your office are still brightly lit Stacks of heavy lesson preparation materials Carrying the responsibility and mission of Lide Shuren Busy student work Working overtime for scientific research in the middle of the night Two-day teaching task The "easyness" we imagined Has nothing to do with your life You have never complained or regretted Be willing to guide students' dreams For teachers who are with the classroom There is nothing more demanding than "teaching, preaching, solving puzzles" It's not an extravagance to make a saint I just hope this insatiable teaching Can bring a warm heart to society Take the initiative to shoulder the identity of the parent Take care of every student who leaves home to study Care and concern Let the students feel the warmth and sweetness of home A piece of chalk, two sleeves Three-foot podium, four seasons Preaching and teaching, keep improving The way you were in class Dear, cute, respectable Delve into the classroom But true academics never stop here Explore the micro world and experience everything in the world You lead us step by step to a new field I want to use a blackboard eraser to remove the wrinkles around your eyes I want to trace your upright youth with chalk I want to give you a light kiss from the lamp before the case late at night All thanks and best wishes are gathered in the pen Translated into a sentence, "Teacher, you have worked hard!"

In the first half of 2020, the emergence of the "black swan" of the new crown virus epidemic has caused severe damage to the global economy. The risk of the economy from weakening to recession has increased significantly, financial market intensified turbulence, supply and demand are facing shrinking, and global trade growth has stagnated. The escalation of geopolitical conflicts, the frequent occurrence of extreme weather events, the remaining uncertain risks of global trade frictions, and the negative effects of the previous Sino-US trade frictions have not been exhausted, and China's home appliance industry exports have been affected to a certain extent. Significant decline in the first quarter, recovery in the second quarter From January to June 2020, the cumulative export value of China's household appliance industry was US$35.24 billion, a year-on-year decrease of 2.3%. Among them, the first quarter fell 12.8% year-on-year, and the second quarter recovered somewhat, with an increase of 10.9% in April, a decrease of 3.3% in May, and an increase of 14.19% in June. Although at the beginning of 2020, due to the epidemic, domestic companies cannot start work on time, and it is difficult to deliver orders. However, after entering March, with the orderly progress of the resumption of work and production, the delivery of the backlog of orders in the early stage has accelerated, and the export market has recovered. Exports increased by 10.9% in April, which is speculated to be mainly due to companies' accelerating delivery of pre-orders. Entering May, foreign countries have entered a period of social isolation, and the overall export of home appliances has fallen again. In June, with the further recovery of overseas demand, the export volume turned positive again. Exports of large/small home appliances and parts continue to differentiate, and air-conditioning maintains positive growth From January to June 2020, the export of large and small home appliances and parts continued to differentiate. The export volume/value of large household appliances maintained small fluctuations, while the export volume/value of small household appliances and parts and components dropped significantly, and the decline was the largest in the past 10 years. Among them, the cumulative export volume of major home appliances was 120 million units, an increase of 4.2% year-on-year, and the cumulative export value was US$14.42 billion, a year-on-year decrease of 0.41%; the cumulative export volume of small household appliances was 1.16 billion units, a year-on-year decrease of 4.67%, and the cumulative export value was 148.1 Billion US dollars, an increase of 0.7% year-on-year; the cumulative export of parts and components was US$ 6.02 billion, a year-on-year decrease of 12.82%. In terms of major appliances, in June, exports of air conditioners, freezers, and microwave ovens continued the positive growth trend in April and May. The export volume of air conditioners in June was 5.46 million units, a year-on-year increase of 9.94%. The cumulative export volume from January to June was 39.857 million units, a year-on-year increase of 9.8%; the export volume of refrigerators in June was 210 units, a year-on-year increase of 46.9%, from January to June. The cumulative export volume was 9.42 million units, a year-on-year increase of 20.93%; the export volume of microwave ovens in June was 5.488 million units, a year-on-year increase of 11.62%. The cumulative export volume from January to June was 28.21 million units, a year-on-year decrease of 3.2%, and the cumulative export value fell year-on-year 5.36%. The export volume of large home appliances generally outperformed the export volume, indicating that the price competition for export orders has been fierce. In terms of small household appliances, with the exception of indoor comfort and electric appliances, all categories have continued the double-digit decline this year, and most of them have fallen for the first time in recent years. In terms of sub-categories, from January to June, the export volume of vacuum cleaners continued to lead, with a year-on-year decrease of 0.13%; the scale of electric fans remained second, with a year-on-year increase of 4.1%; electric roasters were one of the poorly performing categories, with a decrease of 0.13%. 6.45%; coffee machines dropped the most at 23.14%; hair dryers, electric shavers, and irons all dropped rapidly. In addition, the export value of some small household appliances increased year-on-year in June. Vacuum cleaners increased by 24.7% year-on-year, electric fans increased by 39.3% year-on-year, food processors increased by 48.28% year-on-year, and health appliances increased by 55.49% year-on-year. In addition, among the products that accounted for a small share of total exports, exports of water purifiers, drinking fountains, and electric frying pans also quickly returned to normal, and the cumulative export value in the first half of the year increased year-on-year. Among them, drinking fountains increased by 4.3%, and water purifiers Increased by 32%, electric frying pan increased by 57%. In terms of parts and components, from January to June, the cumulative export volume/value of refrigeration compressors all declined, by 7% and 9.9% respectively. Among them, air-conditioning compressor exports fell by 8.8% year-on-year, and refrigerator compressors fell 11.4% year-on-year. Their exports in June fell by 32% and 27% respectively; air-conditioning components maintained a small double-digit decline this year. The products with continuous growth in exports in the second quarter are mainly divided into two categories. The first category is the products that are coming in the overseas consumption season, such as air conditioners and electric fans. According to the rhythm of previous years, after the Spring Festival, air conditioners entered the peak season for export. However, due to the impact of the epidemic, the exports of many companies were affected from February to March. Exports are being expedited from April to May to prepare for the upcoming northern hemisphere. summer. The second category is home appliances whose demand has increased under the influence of the epidemic. Microwave ovens, food processors, vacuum cleaners and other products are all good helpers for "home life". The demand for these products generally increased slightly, and the export orders of enterprises also increased slightly. In addition, due to the insufficient supply of meat products caused by the outbreak of epidemics in meat processing plants around the world, orders for products such as refrigerators and refrigerators have increased rapidly. Especially in North America, from January to June, the cumulative export of compact refrigerator products to the United States was 3.23 million units, a year-on-year increase of 31.8%; the export of refrigerator products to the United States was 2.15 million units, a year-on-year increase of 79%. Continued differentiation in exports to major countries and regions In the first half of 2020, the export performance of home appliances to major countries and regions varied. Cumulative exports to Asia and Oceania have achieved positive year-on-year growth, with a slight decline in European and American markets, and a sharp decline in Latin America. In terms of regions, the cumulative export value of home appliances to Asia increased by 0.04% year-on-year, and the global share was 38.9%, ranking first in scale. Cumulative exports to Europe fell by 2.02% year-on-year, 3.1 percentage points narrower than in May. The four consecutive years of rapid growth has been broken, accounting for 26.2% of total global exports, basically the same as last year, ranking second. . Cumulative exports to North America fell by 2.7% year-on-year, and the decline has narrowed to single digits, with a global share of 22.6%, ranking third for three consecutive years, mainly due to the decline in small home appliances. Exports to Latin America fell by 12.7% year-on-year. It was the only region whose export value continued to decline in June, with a decline of 6.4%, the worst performance among all economic regions. Large appliances, small home appliances, and parts all declined simultaneously. They were 11.2%, 16.9% and 9.9% respectively. China's home appliance industry's exports to Africa fell 9.88% year-on-year, breaking the two-year recovery growth trend. Exports to Oceania turned positive, and the cumulative export value increased by 4.56% year-on-year, making it one of the regions that performed better. In terms of exports to various countries, from January to June, the cumulative export volume to the EU, the United States, Japan and other regions and countries all declined slightly. Among them, the cumulative export value to the United States decreased by 2.65% year-on-year, the export value of major home appliances increased by 1.9% year-on-year, and the export value of small household appliances decreased by 2.43% year-on-year. The decline was further narrowed compared with May. Among them, in the export volume in June, the growth rate of refrigerators, freezers, and refrigerators all reached double digits. Cumulative exports to the EU and the UK fell by 5.4% year-on-year, breaking the steady growth of the last five years, and exports to the core EU countries fell 1% year-on-year. Among them, major appliances increased by 10.8% year-on-year, and small household appliances decreased by 3.8% year-on-year. Among large home appliances, air conditioners continued to outperform, with cumulative export volume and export value increasing by 76.5% and 56.4% year-on-year, respectively. Export volume and export value in June increased by 119.3% and 78.2% year-on-year, respectively, which is the main engine for the growth of major appliances. Cumulative exports to Japan fell by 4% year-on-year, of which large home appliances increased by 0.9% year-on-year, reversing the negative growth this year; small household appliances and parts fell by 2% and 15.4% respectively. Among large household appliances, refrigerators and freezers have a very obvious pulling effect. The cumulative export value of the two increased by 4% and 69.4% year-on-year respectively. The volume of freezers in June increased by 75% and 72% respectively; air conditioners and washing machines continued to be sluggish; microwave ovens increased by 8.8 %. Among small household appliances, coffee machines, vacuum cleaners, and electric fans all fell by about 20%, but food processing machines increased by 16.2% year-on-year. Most of the products exported to Japan are produced and sold back by Japanese companies in China, and the performance of exports to Japan is often positively correlated with the domestic market. According to statistics from the Japan Electrical Industry Association, from January to April 2020, Japan's domestic appliance shipments totaled approximately 631.7 billion yen, a year-on-year decrease of 5.3%. Among them, refrigerators decreased by 20.3% year-on-year, washing machines decreased by 14.7% year-on-year, electric water heaters increased by 13.7% year-on-year, and vacuum cleaners increased by 32.3% year-on-year. The rapid growth of China's exports of refrigerators to Japan may be related to the transfer of orders caused by the closure of some factories in Japan due to the epidemic. In the first half of the year, the cumulative export value of China's household appliance industry to ASEAN countries increased by 19.3% year-on-year, and the growth rate further expanded by nearly 3 percentage points. It has maintained steady growth in the past eight years, which is the main driving force supporting China's household appliance export growth this year. Among large household appliances, air conditioners increased by 25.86% year-on-year, which was the only category that achieved growth. The cumulative export value of refrigerators, freezers, and washing machines all declined slightly year-on-year, but the export volume and export value of refrigerators in June increased significantly by 41.3% and 18.8% year-on-year. To pull action. The growth was mainly in Thailand, Singapore, Indonesia and Vietnam. We speculate that there are two main reasons for the substantial increase in China's household appliance industry exports to the ASEAN region. On the one hand, Southeast Asia has done better in terms of epidemic control, and the internal economic order in Asia has been maintained, which is conducive to enterprises' trading activities; on the other hand, under the background that the Sino-US trade war is still continuing, some products "borrow" ASEAN countries export to avoid the impact of tariffs imposed by the United States. In general, China's home appliance exports have shown strong resilience in the face of the global epidemic. On the one hand, in the early stage of the epidemic, various national ministries and commissions conducted multiple investigations into the severe export situation, further implemented measures to stabilize foreign trade, and adopted various trade facilitation measures to help companies further improve export efficiency; on the other hand, some Overseas electrical appliance manufacturers had to temporarily close their production bases during the epidemic. For example, BSH temporarily closed its plants in North Carolina, the United States in March and May, and Whirlpool temporarily closed its plants in Iowa and Oklahoma in March and June. Samsung also temporarily closed its plants in Iowa and Oklahoma. Many overseas production bases in India, Europe, and the United States have been closed. The production rhythm of many overseas countries has been in an intermittent and unconventional state for the past two months. As the first country to resume work and production, and both upstream and downstream have returned to the normal production rhythm, China has steadily provided various home appliances to consumers in various countries during this special period of the epidemic, and the advantages of the industrial chain have been further highlighted.

Excessive temperature has many negative effects on the stepper motor. In the case of overload operation, the stepper motor will generate a lot of heat, which is easy to cause problems such as damage to the stepper motor. Excessive temperature will first demagnetize the magnetic material of the motor, resulting in a decrease in torque and even loss of step. Therefore, the maximum temperature allowed on the motor surface should depend on the demagnetization point of different motor magnetic materials; generally speaking, a qualified stepper motor magnetic The demagnetization point of the material is above 130 degrees Celsius, so the external temperature of the stepper motor is completely normal at 80-90 degrees Celsius. The surface temperature of the stepper motor can be controlled to reach a balance. The temperature of the stepper motor is often high voltage and high current, because users need high speed and high torque. For example, the surface temperature of a three-phase stepper motor often reaches 95 degrees or more. , Increasing voltage and current can increase the speed and torque. Although the heating of the stepper motor does not cause damage to the stepper motor, it will also cause temporary demagnetization after the temperature is too high. Working under long-term high temperature conditions will also cause permanent magnetic attenuation and coil aging. This is the main reason why some stepping motors have insufficient torque after more than a year.

As a differentiated product, the smart toilet has attracted the attention of many consumers in the bathroom market. Because it has changed the use and structure of traditional toilets in design, it has even surpassed its own product use significance to a certain extent, and its added value is reflected in the aspects of health care, cleaning, etc. However, with the popularity of smart toilets, more consumers are considering the self-cleaning function of the motor and more intelligent toilet applications. PICTURES REFERENCE CHARACTERISTICS MODEL ITEMS SPEC 24BYJ48-187D Rated Voltage 5VDC Phase 4 Reduction Ratio 1/64 Steo Angle 5.625° Exciting Method 1-2 Direct-current Resistance 21Ω±10%(25°C) No-load pull-in Frequency ≥500Hz No-load pull-out Frequency ≥1000Hz pull-in Torque ≥90mN.m(5VDC.800Hz) Detent Torque ≥50mN.m Insulation Resistance ≥50M Ω 500VDC Dielectric Strenght 600VAC Insulation Class B Noise ≤40dB Friction Torque 60-294mN.m Terminal Sec 5P*1.25 OUTLINE APPLICATION SCENARIOS PARTNER