★What is a motor?

Answer: The motor is a component that converts battery electrical energy into mechanical energy to drive the wheels of the electric vehicle to rotate.

★What is a winding?

Answer: The armature winding is the core part of the DC motor and is a coil wound by copper enameled wire. When the armature winding rotates in the magnetic field of the motor, electromotive force is generated.

★What is a magnetic field?

A: The force field that occurs around the permanent magnet or current and the range of space or magnetic force that can be reached by any magnetic force.

★What is magnetic field strength?

Answer: Define the magnetic field strength of an infinite wire carrying 1 ampere of current as 1A/m (ampere/m, international system SI) at a distance of 1/2 m from the wire; In the CGS unit system (cm-g-sec), in order to commemorate Oster's contribution to electromagnetism, the magnetic field strength of an infinite wire carrying 1 ampere of current is defined as 10e (Oster) at a distance of 0.2cm, 10e = 1/4.103/m, the magnetic field strength is usually expressed by H.

★What is the Ampere rule?

Answer: Hold the wire with your right hand so that the direction of the straight thumb is consistent with the direction of the current, then the direction pointed by the curved four fingers is the surrounding direction of the magnetic induction line.

★What is a 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 magnetic induction intensity B and area S, which is called magnetic flux passing through this plane.

★What is a stator?

Answer: The part that does not turn when there is a brush or brushless motor. The motor shaft of a hub-type brushed or brushless toothless motor is called a stator, and this motor can be called an internal stator motor.

★What is a rotor?

Answer: There is a brush or brushless motor that rotates when working. The housing of a hub-type brushed or brushless toothless motor is called a rotor, and this type of motor can be called an external rotor motor.

★What is carbon brush?

Answer: The brush motor is placed on the surface of the inverter. When the motor rotates, the electric energy is transmitted to the coil through the inverter. Because its main component is carbon, it is called carbon brush, which is easy to wear. Should be regularly maintained and replaced, and clean up carbon deposits.

★What is a brush grip?

A: A mechanical guide groove that holds and maintains the position of the carbon brush in the brush motor.

★What is a phase changer?

Answer: The brush motor has a strip-shaped metal surface 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 alternating changes in the current direction of the motor coil and complete the brush motor coil Commutation.

★What is phase sequence?

Answer: The order of the coils of the brushless motor.

★What is magnetic steel?

Answer: It is generally used to call magnetic materials with high magnetic field strength. Electric vehicle motors use NdFeB rare earth magnetic steel.

★What is electromotive force?

Answer: The rotor of the motor cuts the magnetic lines of force, 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 commutator rotate, but the magnetic steel and carbon brush do not rotate. The alternating change of the coil current direction is completed by the commutator and brush rotating with the motor. Brush motors in the electric vehicle industry are divided into high-speed brush motors and low-speed brush motors. There are many differences between brush motors and brushless motors. It can be seen from the words that brush motors have carbon brushes and brushless motors have no carbon brushes.

★What is a low speed brush motor? What are the characteristics?

Answer: In the electric vehicle industry, a low-speed brushed motor refers to a hub-type low-speed high-torque gearless brushed DC motor. The relative speed of the stator and rotor of the motor is the speed of the wheel. The magnet on the stator is 5 to 7 pairs, and the number of slots in the rotor armature is 39 to 57. Since the armature winding is fixed in the wheel housing, heat is easily dissipated by means of the rotating housing. The rotating shell is woven with 36 spokes, which is more conducive to heat conduction. Technical training micro signal is worth your attention!

★Features of motor with brush teeth?

Answer: Because there are brushes in the brush motor, its main hidden danger is "brush wear". Users should note that the brush motor is divided into two kinds of teeth and no teeth. At present, many manufacturers choose a brush and toothed motor, which is a high-speed motor. The so-called "toothed" is to reduce the motor speed through a gear reduction mechanism (because the national standard stipulates that the speed of electric vehicles shall not exceed 20 kilometers per hour, the motor speed should be At about 170 revolutions per minute). Because it is a high-speed motor through gear deceleration, its characteristic is that the rider feels strong power when starting, and the climbing ability is strong. However, the electric wheel hub is closed, and it is only filled with lubricant before leaving the factory. It is difficult for users to perform daily maintenance, and the gear itself also has mechanical wear. The lack of lubrication causes the gear wear to increase, the noise increases, and the current during use. Increase, affecting the life of the motor and battery.

★What is a brushless motor?

Because the controller provides different current directions of direct current, to achieve the alternating direction of the coil current inside the motor. There are no brushes and commutators between the rotor and the stator of the brushless motor.

★How does the motor achieve commutation?

Answer: When a brushless or brushed motor is rotating, the direction of energization of the coil inside the motor needs to be changed alternately, so that the motor can rotate continuously. The commutation of the brush motor is completed by the commutator and the brush, and the brushless motor is completed by the controller.

★What is lack of phase?

Answer: One phase of the three-phase circuit of the brushless motor or brushless controller cannot work. The missing phase is divided into the main phase missing phase and the Hall missing phase. Performance for motor jitter can not work, or weak rotation and noise. The controller is easy to burn when working in the state of lack of phase.

★What are the common types of motors?

Answer: Common motors are: brushed toothed hub motor, brushed toothless hub motor, brushless toothed hub motor, brushless toothless hub motor, side-mounted motor, etc.

★How to distinguish high and low speed motors from the types of motors?

Answer: A brushed toothed hub motor and brushless toothed hub motor are high-speed motors;

B Brushed toothless hub motor and brushless toothless hub motor belong to 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 the power of the motor?

Answer: The choice of motor rated power is a very important and complicated problem. When the load, if the motor rated power is too large, the motor is often in light load operation, the capacity of the motor itself can not be fully utilized, into a "big horse-drawn car", while the motor operating efficiency is low, the performance is not good, will increase the operating costs. On the other hand, the rated power of the motor is required to be small, that is, "small horse-drawn cart". The current of the motor exceeds the rated current, the loss in the motor increases, and when the efficiency is low, the important thing is to affect the life of the motor. Even if the overload is not large, the life of the motor will be reduced more. More overload will destroy the insulation performance of the motor insulation material or even burn down. Of course, the motor rated power is small, may not drag the load, will make the motor for a long time in the starting state and overheating damage. Therefore, the rated power of the motor should be selected in strict accordance with the operation of the electric vehicle.

★Why do general brushless DC motors have three Hall?

Answer: Briefly, in order to rotate a brushless DC 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, to a certain extent, the magnetic field direction of the stator coil must be changed. So how do you know to change the direction of the stator magnetic field? That depends on the three Hall. Those three Halls can be thought of as tasked with telling the controller when to change the direction of the current.

★What is the approximate range of power consumption of brushless motor Hall?

Answer: The power consumption of brushless motor Hall is roughly in the range of 6mA-20mA.

★How high temperature can the general motor work normally? How high temperature can the motor withstand at most?

Answer: If the temperature of the 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 wound by enameled wire, and the enameled wire will fall off because the temperature is too high when the temperature is higher than about 150 degrees, resulting in a short circuit of the coil. When the coil temperature is above 150 degrees, the motor shell shows a temperature of about 100 degrees, so if the temperature of the shell is based on the maximum temperature of 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 more than 20 degrees Celsius?

Answer: The direct cause of the motor fever is caused by the large current. Generally, it may be caused by short circuit or open circuit of coil, demagnetization of magnetic steel or low efficiency of motor, while the normal situation is that the motor runs at 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 a 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 at which the motor temperature is higher than the ambient temperature is called temperature rise. Once there is a temperature rise, the motor will dissipate heat to the surrounding; the higher the temperature, the faster the heat dissipation. When the heat emitted by the motor per unit time is equal to the heat emitted, the motor temperature no longer increases, but maintains a stable temperature, that is, in a state of balance between heat and heat dissipation.

★Generally, what is the allowable temperature rise? Which part of the motor has the greatest impact on the temperature rise of the motor? How is it defined?

Answer: When the motor is running under load, starting from trying to play its role, the greater the load, the better the output power (if the mechanical strength is not considered). But the greater the output power, the greater the power loss, the higher the temperature. We know that the weakest thing in the motor is insulating materials, 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 aspects of insulating materials are stable, and their working life is generally about 20 years. Beyond this limit, the life of the insulating material is drastically shortened and even burned. 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, 40 degrees Celsius is the standard ambient temperature in China. 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. Five. Based on the ambient temperature of 40 degrees Celsius, the five insulating materials and their allowable temperature and allowable temperature rise are shown in the following table:

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 with improved heat resistance organic paints as binders 130 90

F Mica, asbestos and glass fiber compositions bonded or impregnated with epoxy resins with excellent heat resistance 155 115

H mica, asbestos or glass fiber composition bonded or impregnated with silicon resin, silicon rubber 180 140

★How to measure the phase angle of a brushless motor?

Answer: Turn on the power of the controller and the controller supplies power to the Hall element to detect the phase angle of the brushless motor. The method is as follows: use the 20V DC voltage range of the universal meter, connect the red pen to the 5V line, measure the high and low voltages of the three leads respectively with the black pen, and compare them with the commutation tables of the 60-degree and 120-degree motors.

★Why can't any brushless DC controller and brushless DC motor rotate normally when they are connected at will? Why does brushless DC have reverse phase sequence?

Answer: Generally speaking, the actual movement of a brushless DC motor is such a process: the motor rotates-the direction of the rotor magnetic field changes-when the angle between the stator magnetic field direction and the rotor magnetic field direction reaches 60 degrees of electrical angle-Hall signal changes-phase line current direction changes-the stator magnetic field moves forward across 60 degrees of electrical angle-the angle between the stator magnetic field direction and the rotor magnetic field direction is 120 degrees of electrical angle-the motor continues to rotate. In this way we understand that Hall has six correct states. When a specific Hall tells the controller, the controller has a specific phase line output state. Therefore, the reverse phase sequence is to complete 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?

Answer: It will all fall to the phenomenon of lack of phase and cannot rotate normally; but the controller used by Jetenergy is an intelligent brushless controller that can automatically identify 60-degree motors or 120-degree motors, so that two motors can be compatible and adapted. Make maintenance and replacement more convenient.

★How can 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 line are plugged in with the corresponding wires on the controller, and there are 36 connections between the three motor Hall lines and the three motor lines to the controller. The simplest and stupid method is to test each state one by one. The change can be carried out without electricity, but it must be done carefully and in a certain order. Attention should be paid to not turning too much each time. If the motor does not rotate smoothly, this state is wrong. If the turning handle is too large, it will damage the controller. If there is a reverse rotation, if the phase sequence of the controller is known, the Hall lines A and C of the controller are interchanged. Click on the lines A and B to interchange, and then the controller can be turned forward. Finally, it is verified that the correct method of connection is normal when large current is running.

★How to control a 120 degree motor with a 60 degree brushless controller?

Answer: The direction line can be added between the Hall signal line B of the brushless motor and the sampling signal line of the controller.

★What is the intuitive difference between a brush high-speed motor and a brush low-speed motor?

Answer: A. The high-speed motor has an overrunning clutch, which makes it easy to turn in one direction and exhausts to turn in the other direction; the low-speed motor is as easy as two-way rotation.

B. The noise of the high-speed motor is larger when the car rotates, and the noise of the low-speed motor is smaller. Experienced people can easily identify by ear.

★What is the rated operating 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 operating state. When working in the rated operating state, the motor can run reliably and has the best overall performance.

★How is the rated torque of the motor calculated?

Answer: the rated torque output on the click axis can be expressed by T2n, and its magnitude is the rated value of the output mechanical power divided by the rated value of the transfer speed, I .e. T2n = Pn, where the unit of Pn is w, the unit of Nn is r/min, and the unit of T2n is n m. if the unit of PNM is KN, the coefficient 9.55 is changed to 9550.

Therefore, it can be concluded that if the rated power of the motor is equal, the lower the speed of the motor, the greater the torque.

★How is the starting current of the motor defined?

Answer: Generally, the starting current of the motor should not exceed 2 to 5 times of its rated current, which is an important reason why the current limiting protection is made on the controller.

★Why is the speed of the motor sold on the market getting higher and higher? And what is the impact?

A: Speeding up by suppliers can reduce costs. It is also a low-speed click. If the speed is high, the number of turns of coils will be reduced. It also saves silicon steel sheets and the number of magnetic steel. Buyers think that high speed is good.

When the rated speed is working, its power is unchanged, but the efficiency is obviously low in the low speed zone, that is, the starting is weak. The efficiency is low, it needs to be started with a large current, the current is also large when riding, the current limiting requirement of the controller is large, and it is not good for the battery.

★How to repair the abnormal heating of the motor?

Answer: The method of maintenance treatment is generally to replace the motor or 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 causes? How to repair

Answer: Click on the internal mechanical friction is large; the coil is partially short-circuited; the magnetic steel is demagnetized; the DC motor phase changer has carbon deposits. The general method of maintenance treatment is to replace the motor, or replace the carbon brush, and clean up the carbon deposit.

★What is the maximum fault-free limit no-load current for various motors?

Motor type rated voltage 24V rated voltage 36V

Side motor 2.2A 1.8A

High speed brush 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 motor idling current?

Answer: Place the multimeter in the 20A position and connect the red and black probe to the power input of the controller. Turn on the power supply and record the maximum current A1 of the multimeter when the motor does not rotate. Rotate the rotating handle to make the motor rotate at high speed and no load for more than 10s. After the motor speed is stable, observe and record the maximum value A2 of the multimeter at this time. Motor no-load current = A2-A1.

★comparison of commonly used electric car motor:

Motor form transmission form motor efficiency climbing performance maintenance cycle volume maintenance content noise cost

Brushless toothless brushless low-speed external rotor motor, direct drive> 80% generally no big, no small and low

Brushless toothed high-speed brushless motor, planetary gear deceleration> 83% good about 3 years small lubrication gear medium and high

Brushed toothed high-speed brushed motor, stage 2 gear reduction <78% good for about 1 year, large replacement of carbon brushes and large height of lubricating gears

Brushed toothless low-speed brushed outer rotor motor, direct drive <76% difference about 2 years small replacement of carbon brushes, cleaning of carbon deposits

★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, compared with normal values, and the level of motor efficiency and torque, as well as the noise, vibration and calorific value of the motor. The best way is to test the efficiency curve with a dynamometer.

★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 is the riding current of an electric vehicle different due to the rating of the motor in a standard environment?

Answer: As we all know, under standard conditions, based on the 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 rated efficiency points of the two motors 250W and 350W are 80%, the rated working current of the 250W motor is about 6.5A, while the rated working current of the 350W motor is about 9A. However, the efficiency point of a general motor is that the farther the working current deviates from the rated working current, the smaller its value. Under the load of 4-5A, the efficiency of a 250W motor is 70%, and the efficiency of a 350W motor is 60%, then under the load of 5A,

The output power of 250W is 48V * 5A * 70% = 168W

The output power of 350W is 48V * 5A * 60% = 144W

However, in order to make the output power of the 350W motor meet the riding requirements, that is, 168W (almost the rated load), the only way to increase the power supply is to increase the efficiency point.

★Why in the same environment, 350W motor than 250W motor electric car mileage is shorter?

Answer: Under the same environment, the electric vehicle with 350W motor has a large riding current, so under the condition of the same battery, its continuous mileage will be short.

★For electric scooter manufacturers should be how to choose the motor? According to what to choose the motor?

Answer: For electric vehicles, the most critical factor in the choice of motor is the choice of motor rated power.

Motor rated power selection is generally divided into three steps:

The first step is to calculate the load power P

The second step is to preselect the rated power of the motor and others according to the load power.

The third step is to check the pre-selected motor. Generally, the heat temperature rise is checked first, then the overload capacity is checked, and the startup capacity is checked if necessary. All passed, the pre-selected motor was selected; it will not pass from the second step until it is passed.

Do not meet the requirements of the load, the smaller the rated power of the motor, the more economical.

After the second step is done, the temperature correction should be carried out according to the different ambient temperature, and the rated power is carried out under the premise of the national standard ambient temperature of 40 degrees Celsius. If the ambient temperature is low or high all the year round, make full use of the capacity of the motor in the future, and correct the rated power of the motor. For example, the perennial temperature is low, the rated power of the motor century should be higher than the standard Pn, on the contrary, the perennial temperature is high, the rated power should be reduced.

Generally speaking, when the ambient temperature is determined, the motor of the electric vehicle should be selected 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 riding state is generally determined according to the road conditions. If the road surface in Tianjin is smooth, the low-power motor is sufficient; if a higher-power motor is used, it will cause a waste of energy and short mileage. If there are many mountain roads in Chongqing, it is suitable to use a larger motor.

★A 60-degree brushless DC motor is more powerful than a 120-degree brushless DC motor, right? Why?

A: From the market, it is found that there is such a fallacy when communicating with many customers! The 60-degree motor is considered stronger than the 120-degree motor. We think this is probably the production of 60 degrees brushless motor manufacturers of a propaganda. From the principle of brushless motor and the facts have proved that, in fact, 60 degree motor or 120 degree motor! The so-called degree is only used to tell the brushless controller when to turn on which two phase wires it is thinking about. There is no one more powerful than the other! The same is true for 240 degrees and 300 degrees. No one is more energetic than anyone else.