★What is a motor?A: The motor is a component that converts battery electrical energy into mechanical energy and drives the wheels of an electric vehicle to rotate.★What is winding?Answer: The armature winding is the core part of the DC motor, which is a coil made of copper enameled wire. Electromotive force is generated when the armature winding rotates in the magnetic field of the motor.★What is a magnetic field?Answer: The force field that occurs around the permanent magnet or the current and the space or the range of the magnetic force that the magnetic force can reach.★What is the magnetic field strength?Answer: Define the magnetic field strength of an infinitely long wire carrying a current of 1 amp at a distance of 1/2 m from the wire as 1A/m (Ampere/meter, SI); in CGS units (cm-gram-second) , in order to commemorate Oersted's contribution to electromagnetism, define the magnetic field strength of an infinite wire carrying a current of 1 ampere at a distance of 0.2 cm from the wire as 10e (Oersted), 10e=1/4.103/m, the magnetic field Intensity is usually denoted by H.★What is Ampère's Law?Answer: Hold the wire with the right hand, and make the direction of the straight thumb consistent with the direction of the current, then the direction pointed by the four curved fingers is the surrounding direction of the magnetic field line.★What is magnetic flux?Answer: Magnetic flux is also called magnetic flux: there is a plane perpendicular to the direction of the magnetic field in a uniform magnetic field, the magnetic induction intensity of the magnetic field is B, and the area of the plane is S, we define the product of the magnetic induction intensity B and the area S, which is called passing through magnetic flux on this surface.★What is a stator?Answer: The part that does not rotate when the brush or brushless motor works. The motor shaft of the hub-type brushed or brushless gearless motor is called the stator, and this type of motor can be called an inner stator motor.★What is a rotor?Answer: The part that rotates when a brush or brushless motor works. The housing of the hub-type brushed or brushless gearless motor is called the rotor, and this type of motor can be called an outer rotor motor.★What is a carbon brush?Answer: The brushed motor rests on the surface of the commutator. When the motor rotates, the electric energy is delivered to the coil through the phase converter. Because its main component is carbon, called carbon brush, it is easy to wear. It should be regularly maintained and replaced, and the carbon deposits should be cleaned up.★What is a brush grip?A: The mechanical guide groove that holds and maintains the position of the carbon brush in the brushed motor.★What is a commutator?Answer: In the brushed motor, there are strip-shaped metal surfaces that are insulated from each other. When the motor rotor rotates, the strip-shaped metal alternately contacts the positive and negative poles of the brush to realize the positive and negative change of the current direction of the motor coil, and complete the brushed motor coil. commutation.★What is phase sequence?Answer: The arrangement order of the brushless motor coils.★What is a magnet?Answer: It is generally used to call magnetic materials with high magnetic field strength. Electric vehicle motors use neodymium-iron-sodium rare-earth magnets.★What is electromotive force?Answer: It is generated by the rotor of the motor cutting the magnetic field lines, and its direction is opposite to the external power supply, so it is called back electromotive force.★What is a brushed motor?Answer: When the motor is working, the coil and the commutator rotate, but the magnetic steel and the carbon brush do not rotate. The alternating change of the current direction of the coil is accomplished by the commutator and brush that rotate with the motor. In the electric vehicle industry, brushed motors are divided into high-speed brushed motors and low-speed brushed motors. There are many differences between brushed motors and brushless motors. It can be seen from the words that brushed motors have carbon brushes, and brushless motors do not have carbon brushes.★What is a low-speed brushed motor? What are the characteristics?Answer: In the electric vehicle industry, the low-speed brushed motor refers to a hub-type low-speed high-torque brushless DC motor without gear transmission. The relative speed of the stator and rotor of the motor is the speed of the wheel. The number of magnets on the stator is 5~7 pairs, and the number of slots of the rotor armature is 39~57. Since the armature windings are fixed in the wheel housing, the heat is easily dissipated by the rotating housing. The rotating shell is woven with 36 spokes, which is more conducive to heat conduction. Skilled training WeChat account deserves your attention!★What are the characteristics of brushed and toothed motors?Answer: There are brushes in brushed motors, and the main hidden danger is "brush wear". Users should note that brushed motors are divided into two types: toothed and toothless. At present, many manufacturers choose brushed and toothed motors, which are high-speed motors. The so-called "toothed" means to reduce the motor speed through the gear reduction mechanism (because the national standard stipulates that the speed of electric vehicles should not exceed 20 kilometers per hour, so the motor speed should be 170 rpm or so). Because the high-speed motor is decelerated by gears, it is characterized by the rider feeling strong power and strong climbing ability when starting. However, the electric wheel hub is closed, and it is only filled with lubricant before leaving the factory. It is difficult for users to carry out daily maintenance, and the gear itself also has mechanical wear. The lack of lubrication leads to aggravated gear wear and noise in about a year, and the current during use is also reduced. increase, affecting motor and battery life.★What is a brushless motor?Since the controller provides direct current with different current directions, the alternating current direction of the coil in the motor is achieved. There are no brushes and commutators between the rotor and stator of a brushless motor.★How does the motor realize commutation?Answer: When the brushless or brushed motor is rotating, the energization direction of the coil in the motor needs to be alternately changed, so that the motor can rotate continuously. The commutation of the brushed motor is completed by the commutator and the brush, and the brushless motor is completed by the controller.★What is missing phase?Answer: In the three-phase circuit of the brushless motor or the brushless controller, one phase cannot work. The lack of phase is divided into the lack of main phase and the lack of Hall phase. The performance is that the motor shakes and cannot work, or the rotation is weak and the noise is loud. The controller is very easy to burn out when it works in the state of lack of phase.★What are the common types of motors?Answer: Common motors include: brushed and geared hub motors, brushed gearless hub motors, brushless geared hub motors, brushless gearless hub motors, side-mounted motors, etc.★How to distinguish high and low speed motors from the types of motors?Answer: A Brushed and geared hub motors and brushless geared hub motors are high-speed motors;B Brushless and gearless hub motors and brushless gearless hub motors are low-speed motors.★How is the power of the motor defined?Answer: The power of the motor refers to the ratio of the mechanical energy output by the motor to the electrical energy provided by the power supply.★Why choose the power of the motor? What is the significance of choosing motor power?Answer: The choice of motor rated power is a very important and complicated issue. During load, if the rated power of the motor is too large, the motor will often run at light load, the capacity of the motor itself cannot be fully utilized, and it becomes a "big horse-drawn cart". At the same time, the motor has low operating efficiency and poor performance, which will increase running costs. Conversely, if the rated power of the motor is required to be small, it is a "small horse-drawn cart". The motor current exceeds the rated current, the internal loss of the motor increases, and the efficiency is low. The important thing is to affect the life of the motor, even if there is not much overload , the life of the motor will also be reduced more; more overload will damage the insulation performance of the motor insulation material or even burn it. Of course, the rated power of the motor is small, and it may not be able to drag the load at all, which will cause the motor to be in the and be damaged by overheating. Therefore, the rated power of the motor should be selected strictly according to the operation of the electric vehicle.★Why do brushless DC motors have three Halls?Answer: In short, in order to rotate the DC brushless motor, there must always be a certain angle between the magnetic field of the stator coil and the magnetic field of the rotor permanent magnet. The process of rotor rotation is also the process of changing the direction of the rotor magnetic field. In order to make the two magnetic fields have an angle, the direction of the magnetic field of the stator coil must be changed after a certain degree. So how do you know to change the direction of the stator magnetic field? Then it's up to those three Halls. Think of those three Halls as tasked with telling the controller when to change the direction of the current.★What is the approximate range of power consumption of the brushless motor Hall?A: The power consumption of the brushless motor Hall is roughly in the range of 6mA-20mA.★How high temperature can the motor work normally? What is the maximum temperature the motor can withstand?Answer: If the temperature of the measured motor cover exceeds the ambient temperature by more than 25 degrees, it indicates that the temperature rise of the motor has exceeded the normal range. Generally, the temperature rise of the motor should be below 20 degrees. Generally, the motor coil is made of enameled wire, and when the temperature of the enameled wire is higher than about 150 degrees, the paint film will fall off due to the high temperature, resulting in a short circuit of the coil. When the coil temperature is above 150 degrees, the temperature displayed by the motor casing is about 100 degrees, so if it is based on its casing temperature, the maximum temperature the motor can withstand is 100 degrees.★The temperature of the motor should be below 20 degrees Celsius, that is, the temperature of the motor end cover should exceed the ambient temperature by less than 20 degrees Celsius, but what is the reason why the motor heats up more than 20 degrees Celsius?Answer: The direct cause of motor heating is due to the large current. Generally, it may be caused by the short circuit or open circuit of the coil, the demagnetization of the magnetic steel or the low efficiency of the motor. The normal situation is that the motor runs with high current for a long time.★What causes the motor to heat up? What kind of process is this?Answer: When the motor is running under load, there is power loss in the motor, which will eventually become heat energy, which will increase the temperature of the motor and exceed the ambient temperature. The value by which the motor temperature is higher than the ambient temperature is called the ramp-up. Once the temperature rises, the motor will dissipate heat to the surroundings; the higher the temperature, the faster the heat dissipation. When the heat emitted by the motor per unit time is equal to the heat dissipated, the temperature of the motor will no longer increase, but maintain a stable and constant temperature, that is, in a state of balance between heat generation and heat dissipation.★What is the allowable temperature rise in general click? Which part of the motor is most affected by the temperature rise of the motor? How is it defined?Answer: When the motor is running under load, it is necessary to play its role as much as possible, that is, the larger the output power, the better the load (if the mechanical strength is not considered). But the greater the output power, the greater the loss of power, the higher the temperature. We know that the weakest thing in the motor is the insulating material, such as enameled wire. There is a limit to the temperature resistance of insulating materials. Within this limit, the physical, chemical, mechanical, electrical and other properties of insulating materials are very stable, and their working life is generally about 20 years. Exceeding this limit, the life of the insulating material is shortened sharply, and even burns out. This temperature limit is called the allowable temperature of the insulating material. The allowable temperature of the insulating material is the allowable temperature of the motor; the life of the insulating material is generally the life of the motor.The ambient temperature varies with time and place. When designing the motor, it is stipulated that 40 degrees Celsius is taken as the standard ambient temperature in my country. Therefore, the allowable temperature of the insulating material or motor minus 40 degrees Celsius is the allowable temperature rise,The allowable temperature of different insulating materials is different. According to the allowable temperature, the commonly used insulating materials for motors are A, E, B, F, and H. Calculated at an ambient temperature of 40 degrees Celsius, the five insulating materials and their allowable temperatures and allowable temperature rises are shown in the following table:Grade Insulation Material Allowable Temperature Allowable Temperature Rise A Impregnated cotton, silk, cardboard, wood, etc., ordinary insulating paint 105 65 E Epoxy resin, polyester film, green shell paper, tri-acid fiber, highly insulating paint 120 80 B Mica, asbestos, and glass fiber compositions using organic paints with improved heat resistance as binders 130 90 F Mica, asbestos and fiberglass compositions bonded or impregnated with epoxy resins with excellent heat resistance 155 115 H Mica, asbestos or fiberglass compositions bonded or impregnated with silicone resin, silicone rubber 180 140★How to measure the phase angle of brushless motor?Answer: Turn on the power of the controller, and the controller will supply power to the Hall element, then the phase angle of the brushless motor can be detected. The method is as follows: use the +20V DC voltage range of the multimeter, connect the red test lead to the +5V line, and the black pen to measure the high and low voltages of the three leads respectively.★Why can't any BLDC controller and BLDC motor be connected at will to rotate normally? Why does the brushless DC have a phase sequence reversal?Answer: Generally speaking, the brushless DC motor is such a process in actual motion: the motor rotates—the direction of the rotor magnetic field changes—when the angle between the direction of the stator magnetic field and the direction of the rotor magnetic field reaches an electrical angle of 60 degrees— ---Hall signal change----The direction of phase line current changes----The stator magnetic field crosses 60 degree electrical angle forward----The included angle between the stator magnetic field direction and the rotor magnetic field direction is 120 degree electrical angle--- - The motor continues to turn. So we understand that Hall has six correct states. When a specific Hall tells the controller, the controller has a specific phase output state. Therefore, the phase reversal sequence is to accomplish such a task, that is, to make the electrical angle of the stator always step by 60 degrees in one direction.★What happens if a 60-degree brushless controller is used on a 120-degree brushless motor? What about the other way around?Answer: It will fall to the phenomenon of lack of phase and cannot rotate normally; but the controller used by Jieneng is an intelligent brushless controller that can automatically identify 60-degree motor or 120-degree motor, so that it can be compatible with two kinds of motors. Makes maintenance and replacement more convenient.★How can the DC brushless controller and DC brushless motor pour out the correct phase sequence?Answer: The first step is to ensure that the power and ground wires of the Hall wire are well connected with the corresponding wires on the controller. There are 36 ways to connect the three motor hall wires and the three motor wires to the controller. The simple and stupid way is to try each state one by one. When switching, it can be carried out without interruption, but it must be carefully and in a certain order. Be careful not to twist too much each time. If the motor does not rotate smoothly, this state is not right. If the handle is twisted too much, it will damage the controller. If it reverses, know the phase sequence of the controller. In the case of the controller, the Hall lines a and c of the controller are exchanged, and the phase A and B of the click line are exchanged with each other, and the reverse rotation can be reversed. Finally, the correct way to verify the connection is that it is normal during high current operation.★How to control a 60-degree motor with a 120-degree brushless controller?Answer: You can add a direction line between the b-phase of the brushless motor Hall signal line and the controller sampling signal line.★What is the intuitive difference between a brushed high-speed motor and a brushed low-speed motor?Answer: A. The high-speed motor has an overrunning clutch, which is easy to turn in one direction and exhausted in the other direction; the low-speed motor is equally easy to turn the bucket in both directions.B. The high-speed motor makes a lot of noise when the car rotates, and the low-speed motor makes less noise. It is easy for an experienced person to identify by ear.★What is the rated running state of the motor?Answer: When the motor is running, if each physical quantity is the same as its rated value, it is called the rated running state. When working under the rated running state, the motor can run reliably and has the best comprehensive performance.★How is the rated torque of the motor calculated?Answer: The rated torque output on the click axis can be represented by T2n, which is the rated value of the output mechanical power divided by the rated value of the transfer speed, that is, T2n=Pn where the unit of Pn is W, and the unit of Nn is r/min 、 The unit of T2n is NM, if the unit of PNM is KN, the coefficient 9.55 is changed to 9550.Therefore, it can be concluded that if the motor's rated power is equal, the lower the motor's speed, the greater the torque.★How is the starting current of the motor defined?Answer: It is generally required that the starting current of the motor should not exceed 2~5 times of its rated current, which is also an important reason for the current limiting protection on the controller.★Why are the motor rotation speeds on the market getting higher and higher? and what impact?A: The supplier can increase the speed to reduce the cost. It is also a low-speed click. When the speed is high, the number of coil turns will be reduced, and the silicon steel sheet will be saved, and the number of magnetic steel will be reduced. The buyer thinks that the high speed is good.When working at the rated speed, its power remains unchanged, but the efficiency is significantly lower in the low-speed area, that is, it is powerless to start.The efficiency is low, it needs to be started with a large current, and the current is also large when riding, which requires a large current limit of the controller and is not good for the battery.★How to repair the abnormal heating of the motor?Answer: The method of maintenance is generally to replace the motor, or to carry out maintenance.★When the no-load current of the motor is greater than the limit data of the reference table, it indicates that the motor has a fault. What are the reasons? how to repairA: The internal mechanical friction is large; the coil is partially short-circuited; the magnetic steel is demagnetized; the DC motor commutator deposits carbon. The maintenance method is generally to replace the motor, or replace the carbon brush to clean the carbon deposits.★What is the maximum limit no-load current of various motors without failure?When the rated voltage of the motor is 24V, when the rated voltage is 36VSide mounted motor 2.2A 1.8A High-speed brushed motor 1.7A 1.0A Low speed brush motor 1.0A 0.6A High-speed brushless motor 1.7A 1.0A Low speed brushless motor 1.0A 0.6A★How to measure the motor idling current?Answer: Put the multimeter in the 20A gear, and connect the red and black test leads to the power input terminal of the controller. Turn on the power, and record the maximum current A1 of the multimeter at this time when the motor does not rotate. Turn the handle to make the motor rotate at high speed and no load for more than 10s. After waiting for the motor speed to stabilize, start to observe and record the maximum value A2 of the multimeter at this time. Motor no-load current=A2-A1.★Comparison of commonly used motors for electric vehicles:Motor Type Transmission Type Motor Efficiency Climbing Performance Maintenance Cycle Volume Maintenance Content Noise Cost Brushless, toothless, brushless, low-speed outer rotor motor, direct drive > 80% Generally no big, no small, low Brushless toothed high-speed brushless motor, planetary gear reduction > 83% good for about 3 years Small lubricated gear medium high Brushed and toothed high-speed brushed motor, 2-stage gear reduction < 78%, good for about 1 year Brushed and toothless low-speed brushed external rotor motor, direct drive < 76%, about 2 years difference, small replacement of carbon brushes, cleaning of carbon deposits is small and low★How to identify the quality of the motor? What are the key parameters?Answer: It is mainly the size of no-load current and riding current, the comparison with normal values, and the level of motor efficiency and torque, as well as the noise, vibration and heat generation of the motor. The best way is to use a dynamometer to test the efficiency curve.★ What is the difference between 180W and 250W motors? What are the requirements for the controller?Answer: The 250W riding current is large, which requires high power margin and reliability of the controller.★Why in the standard environment, the riding current of the electric vehicle will be different due to the different ratings of the motor?Answer: As we all know, under standard conditions, calculated with a rated load of 160W, the riding current on a 250W DC motor is about 4-5A, while the riding current on a 350W DC motor is slightly higher. For example: If the battery voltage is 48V, and the two motors are 250W and 350W, and their rated efficiency points are both 80%, the rated operating current of the 250W motor is about 6.5A, while the rated operating current of the 350W motor is about 9A. In general, the efficiency point of the motor is that the farther the working current deviates from the rated working current, the smaller the value is. Under the same load condition of 4-5A, the efficiency of the 250W motor is 70%, and the efficiency of the 350W motor is 60%. Under the load of 5A,The output power of 250W is 48V*5A*70%=168WThe output power of 350W is 48V*5A*60%=144WIn order to make the output power of the 350W motor reach 168W (which is almost the rated load) in order to meet the riding requirements, it is only necessary to increase the power supply, thereby increasing the efficiency point.★Why is the continuation mileage of an electric vehicle with a 350W motor shorter than that of a 250W motor in the same environment?A: In the same environment, the electric vehicle with 350W motor has a large riding current, so in the case of the same battery, its continuation mileage will be shorter.★How should electric moped manufacturers choose a motor? According to what to choose the motor?A: For electric vehicles, the most critical factor in motor selection is the selection of motor rated power.Motor rated power selection is generally divided into three steps:The first step is to calculate the load power PThe second step is to pre-select the rated power of the motor and others according to the load power.The third step is to check the preselected motor. Generally, first check the heating temperature rise, then check the overload capacity, and check the starting capacity if necessary. All passed, the pre-selected motor is selected; but the pass is repeated from the second step until it passes.Do not make the motor's rated power smaller the more economical it is under the condition of meeting the load requirements.After the second step is completed, temperature correction should be carried out according to the different ambient temperature. The rated power is carried out under the premise that the national standard ambient temperature is 40 degrees Celsius. If the ambient temperature is low or high all the year round, the capacity of the motor should be fully utilized in the future, and the rated power of the motor should be corrected. For example, if the temperature is low all year round, the rated power of the motor should be higher than the standard Pn. On the contrary, if the temperature is high all year round, the rated power should be reduced.In general, when the ambient temperature is determined, the selection of the motor of the electric vehicle should be determined according to the riding state of the electric vehicle. The more the riding state of the electric vehicle can make the motor close to the rated working state, the better. The driving status is generally determined according to the road conditions. If the road in Tianjin is smooth, a small-power motor is sufficient; if a larger-power motor is used, it will cause waste of energy and short mileage. If there are many mountain roads in Chongqing, it is suitable to use a motor with a higher power.★ 60 degree BLDC motors are stronger than 120 degree BLDC motors, right? Why?A: It is found from the market that there is such a fallacy when communicating with many customers! Think a 60 degree motor is more powerful than a 120 degree motor. We think this is probably a kind of propaganda for the manufacturers of 60 degree brushless motors. From the principle of brushless motor and the fact that it has been proved, in fact, 60-degree motor or 120-degree motor is fine! The so-called degree is only used to tell the brushless controller when to let the two phase wires in mind conduct. There is no one who is more powerful than the other! 240 degrees and 300 degrees are the same, no one is stronger than the other.
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