★ What is an electric motor?

 

A: The motor is a component that converts battery power into mechanical energy and drives the wheel of the electric vehicle to rotate.

 

 

 

★ What is winding?

 

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

 

 

 

★ What is the magnetic field?

 

A: The force field occurring around a permanent magnet or current and the range of space or magnetic force that can be achieved by magnetic force.

 

 

 

★ What is the magnetic field strength?

 

A: Define an infinitely long wire carrying 1 amp of current with a magnetic field strength of 1 A/m (Amp/m, SI unit) at a distance of 1/2 m from the wire; in CGS unit system (cm-g-sec) In order to commemorate Oster's contribution to electromagnetism, define an infinitely long wire carrying 1 amp of current with a magnetic field strength of 10e (Oersted) at a distance of 0.2 cm from the wire, 10e = 1/4.103/m, magnetic field The intensity is usually expressed in H.

 

 

 

★ What is Ampere's rule?

 

A: Hold the wire with your right hand so that the direction of the straightened thumb is the same as the current direction, then the direction of the curved four fingers is the direction around the magnetic line.

 

 

 

★ What is magnetic flux?

 

Answer: Magnetic flux is also called magnetic flux: it is set in a uniform magnetic field with a plane perpendicular to the direction of the magnetic field. The magnetic induction of the magnetic field is B, and the area of ​​the plane is S. We define the product of the magnetic induction B and the area S. The magnetic flux of this face.

 

 

 

★ What is the stator?

 

A: The part that does not turn when the brush or brushless motor works. The motor shaft of a hub-type brushed or brushless toothless motor is called a stator. Such a motor can be called an internal stator motor.

 

 

 

★ What is a rotor?

 

A: The part that is rotated when the brush or brushless motor is working. The outer casing of a hub-type brushed or brushless toothless motor is called a rotor. Such a motor can be called an outer rotor motor.

 

 

 

★ What is a carbon brush?

 

Answer: The brush motor is placed on the surface of the commutator. When the motor rotates, the electric energy is sent to the coil through the phase converter. Since its main component is carbon, it is called carbon brush, which is easy to wear. The replacement should be maintained regularly and the carbon deposits should be cleaned.

 

 

 

★ What is a brush holder?

 

A: A mechanical guide that holds and holds the carbon brush position inside the brushed motor.

 

 

 

★ What is a phase changer?

 

Answer: Inside the brushed motor, there is a strip-shaped metal surface insulated from each other. When the rotor of the motor rotates, the strip-shaped metal alternately contacts the positive and negative poles of the brush to achieve positive and negative alternating current direction of the motor coil, completing the brush motor coil. Commutation.

 

 

 

★ What is the phase sequence?

 

A: The order of the brushless motor coils.

 

 

 

★ What is magnetic steel?

 

A: Generally used for magnetic materials called high magnetic field strength, electric motor motors are made of neodymium iron rare earth magnetic steel.

 

 

 

★ What is electromotive force?

 

Answer: It is generated by cutting the magnetic lines of force from the rotor of the motor. The direction is opposite to the applied power supply, so it is called back electromotive force.

 

 

 

★ What is a brush motor?

 

Answer: When the motor is working, the coil and the commutator rotate, the magnetic steel and the carbon brush do not rotate, and the alternating current direction of the coil is completed by the commutator and the brush that rotate 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 a brush motor and a brushless motor. It can be seen from the word that the brush motor has a carbon brush, and the brushless motor has no carbon brush.

 

 

 

★ What is a low-speed brushed motor? What are the characteristics?

 

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

 

 

 

★The characteristics of brushed toothed motor?

 

Answer: Because there is a brush in the brush motor, the main hidden danger is “brush wear”. Users should notice that the brush motor is 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" is to reduce the motor speed through the gear reduction mechanism. (The speed of the electric vehicle must not exceed 20 kilometers due to the national standard, so the motor speed should be 170 rpm / minute or so). Because the high-speed motor is decelerated by the gear, it is characterized by the rider feeling strong power at the start, and the climbing ability is strong. However, the electric wheel hub is closed, but the lubricant is added before leaving the factory. It is difficult for the user to carry out daily maintenance, and the gear itself also has mechanical wear. The gear wear is increased due to insufficient lubrication for a year or so, the noise is increased, and the current is also used. Increase, affecting motor and battery life.

 

 

 

★ What is a brushless motor?

 

Since the controller provides direct current in different current directions, the alternating current direction of the coil inside the motor is achieved. There are no brushes and commutators between the rotor and the stator of the brushless motor.

 

 

 

★How does the motor achieve commutation?

 

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

 

 

 

★ What is the lack of phase?

 

A: One phase of the three-phase circuit of the brushless motor or brushless controller cannot work. The lack of phase division main phase phase loss and Hall phase loss. It is manifested that the motor shake does not work, or the rotation is weak and the noise is high. The controller works easily in the phase loss state and is easily burned.

 

★What are the common types of motors?

 

Answer: Common electric motors are: brushed gear hub motor, brushless gearless hub motor, brushless gear hub motor, brushless gearless hub motor, side-mounted motor, etc.

 

 

 

★How do you distinguish between high and low speed motors from the type of motor?

 

answer:

 

A brushed geared hub motor, brushless geared hub motor is a high speed motor;

 

B Brushless gearless hub motors, brushless gearless hub motors are low speed motors.

 

 

 

★How is the power of the motor defined?

 

Answer: The power of the motor is the ratio of the mechanical energy output by the motor to the power supplied by the power supply.

 

 

 

★ Why choose the power of the motor? What is the significance of choosing the motor power?

 

A: The choice of rated motor power is a very important and complicated issue. When the load is too high, if the rated power of the motor is too large, the motor will often be in light load operation, and the capacity of the motor itself will not be fully exerted, and it will become a “large horse-drawn car”. At the same time, the motor has low operating efficiency and poor performance, which will increase. Operating expenses. Conversely, the motor's rated power requirements are small, that is, "small horse-drawn cart", the motor current exceeds the rated current, the motor wears more, the efficiency is low, the important thing is to affect the life of the motor, even if the overload is not much 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 the load may not be dragged at all, which may cause the motor to be in a startup state for a long time and be damaged by overheating. Therefore, the rated power of the motor should be selected in strict accordance with the operation of the electric vehicle.

 

 

 

★ Why do general DC brushless motors have three Halls?

 

A: In short, in order to be able to rotate, the DC brushless motor must have a certain angle between the magnetic field of the stator coil and the magnetic field of the permanent magnet of the rotor. The process of rotating the rotor is also the process of changing the direction of the magnetic field of the rotor. In order to make the magnetic field of the two have an angle, the magnetic field direction of the stator coil must be changed to a certain extent. So how do you know the direction of the stator magnetic field? Then rely on the three Halls. It can be thought that the three Halls shoulder the task of telling the controller when to change the direction of the current.

 

 

 

★ What is the approximate 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 can the normal motor work at a high temperature? How high can the motor withstand?

 

A: If the temperature of the motor cover is more than 25 degrees above the ambient temperature, 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 an enameled wire, and when the temperature of the enameled wire is higher than 150 degrees, the paint film may fall off due to excessive temperature, causing the coil to be short-circuited. When the coil temperature is above 150 degrees, the temperature of the motor casing is about 100 degrees, so the maximum temperature of the motor is 100 degrees based on the temperature of the casing.

 

 

 

★The temperature of the motor should be below 20 degrees Celsius, that is, the temperature of the motor cover should exceed 20 degrees Celsius, but what is the reason why the motor heats up to 20 degrees Celsius?

 

Answer: The direct cause of motor heating is caused by large current. Generally, it may be caused by short circuit or open circuit of coil, demagnetization of magnetic steel or low efficiency of motor. Normally, the motor runs for a long time and high current.

 

 

 

★ What causes the motor to heat up? What is the process?

 

Answer: When the motor load is running, there is power loss in the motor, which will eventually become heat energy, which will cause the motor temperature to rise above the ambient temperature. The value at which the motor temperature is higher than the ambient temperature is called temperature rise. Once there is temperature rise, 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 amount of heat dissipated, the temperature of the motor no longer increases, but maintains a constant temperature, that is, a state in which heat and heat are balanced.

 

 

 

★What is the temperature rise for the general click? Which part of the motor is the most affected by the temperature rise of the motor? How is it defined?

 

Answer: When the motor load is running, from the role of playing its role as much as possible, the load with the load is as high as possible (if mechanical strength is not considered). However, the greater the output power, the greater the power loss and the higher the temperature. We know that the weakest temperature resistance in an electric motor is an insulating material, such as an 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 location. When designing the motor, it is required to take 40 degrees Celsius as the standard ambient temperature in China. Therefore, the allowable temperature of the insulating material or the motor minus 40 degrees Celsius is the allowable temperature rise. The allowable temperatures of different insulating materials are different. According to the allowable temperature, the common insulating materials for the motor are A, E, B, F, H. Five kinds. Calculated according to 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:

 

Grade Insulation Material Allowable Temperature Allowable Temperature Rise

 

A immersed cotton, silk, cardboard, wood, etc., ordinary insulating varnish 105 65

 

E Epoxy resin, polyester film, green paper, tri-acid fiber, highly insulating paint 120 80

 

B Mica, asbestos, and fiberglass compositions using an organic paint with improved heat resistance as a binder 130 90

 

F Mica, asbestos and glass fiber compositions bonded or impregnated with heat-resistant epoxy resin 155 115

 

H Mica, asbestos or fiberglass composition bonded or impregnated with silicon resin, silicone with rubber 180 140

 

 

 

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

 

Answer: Turn on the controller power supply, and the controller supplies the Hall element to detect the phase angle of the brushless motor. The method is as follows: use the +20V DC voltage file of the universal meter, and connect the red test lead to the +5V line. The black pen measures the high and low voltages of the three leads respectively, and can be compared with the commutation table of the 60 degree and 120 degree motor.

 

 

 

★Why can any DC brushless controller and DC brushless motor be able to rotate normally without being connected? Why does DC brushless have a reverse phase sequence?

 

A: Generally speaking, the DC brushless motor is a process in actual motion: the rotation of the motor ---- 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 60 degrees of electrical angle - --- Hall signal change ---- phase line current direction change --- stator magnetic field forward 60 degrees electrical angle --- the angle between the stator magnetic field and the rotor magnetic field is 120 degrees electrical angle --- - The motor continues to rotate. So we understand that Hall has six correct states. When a particular Hall tells the controller, the controller has a specific phase output state. Therefore, the reverse phase sequence is to accomplish such a task, that is, the electrical angle of the stator is always stepped at an electrical angle of 60 degrees in one direction.

 

 

 

★ What happens if a 60-degree brushless controller is used on a 120-degree brushless motor? What about the reverse?

 

A: It will fall to the phase loss phenomenon and cannot rotate normally. However, the controller used by Jieneng is an intelligent brushless controller that can automatically recognize the 60-degree motor or the 120-degree motor, so that it can be compatible with the two motors. 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 lines of the Hall line are plugged into the corresponding lines on the controller, and the three motor Hall lines and the three motor line pairs are connected to the controller in total. The simple and clumsy method is to test each state one by one. It can be carried out continuously when changing, but it must be careful and have a certain order. It should be noted that the screwing is not too big every time. If the motor does not rotate smoothly, this state is wrong. If the turning screw is too large, it will damage the controller. If there is a reversal, know the phase sequence of the controller. In the case of the controller Hall lines a, c are interchanged, click on the line A phase and B phase interchange, you can turn into a forward rotation. Finally, verify that the correct method is normal when the high current is running.

 

 

 

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

 

Answer: Add a directional line between the brush signal motor Hall signal line b phase 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 can be easily transferred in one direction and exhausted in the other direction; the low-speed motor is as easy as two-way.

 

B. The high-speed motor has a large noise when the car rotates, and the low-speed motor has less noise. Experienced people are very tolerant