What is a motor?

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

What is winding?

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

What is a magnetic field?

Answer: The force field that occurs around the permanent magnet or the current and the space that the magnetic force can reach or the scope of the magnetic force.

What is magnetic field strength?

Answer: Define the magnetic field strength of an infinitely long wire carrying a current of 1 ampere at a distance of 1/2 meter from the wire to be 1A/m (ampere/meter, SI in the international system of units); in the CGS unit system (cm-gram-second) In , to commemorate Oersted's contribution to electromagnetism, define the magnetic field strength of an infinitely long wire carrying a current of 1 ampere at a distance of 0.2 cm from the wire to be 10e (Oersted), 10e=1/4.103/m, the magnetic field Intensity is usually indicated by H.

What is Ampere's Law?

Answer: Hold the wire with your right hand, and make the direction of the straight thumb coincide with the direction of the current, then the direction pointed by the bent four fingers is the direction of the magnetic induction line.

What is magnetic flux?

Answer: Magnetic flux is also called magnetic flux: Suppose there is a plane perpendicular to the direction of the magnetic field in a uniform 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, 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 is working. The motor shaft of a hub-type brushed or brushless gearless motor is called a stator, and this type of motor can be called an inner stator motor.

What is a rotor?

Answer: The part that rotates when the brush or brushless motor works. The shell 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 inside of the brushed motor is on the surface of the commutator. When the motor rotates, the electric energy is transmitted to the coil through the phase commutator. Because its main component is carbon, it is called a carbon brush, which is easy to wear. It should be regularly maintained and replaced, and carbon deposits should be cleaned.

What is a brush grip?

Answer: The mechanical guide groove that contains and maintains the position of the carbon brush in the brushed motor.

What is a phase commutator?

Answer: Inside 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 alternating positive and negative changes in the direction of the motor coil current and complete the brushed motor coil. commutation.

What is phase sequence?

Answer: The arrangement order of brushless motor coils.

What is a magnet?

Answer: It is generally used to refer to magnetic materials with high magnetic field strength. Electric vehicle motors use NdFeR rare earth magnets.

What is electromotive force?

Answer: It is generated by the rotor of the motor cutting the magnetic force line, and its direction is opposite to that of the external power supply, so it is called counter electromotive force.

What is a brushed motor?

Answer: When the motor is working, the coil and commutator rotate, but the magnetic steel and carbon brushes do not rotate. The alternating change of the coil current direction is accomplished by the commutator and brushes 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 its 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, and the relative speed of the stator and rotor of the motor is the speed of the wheel. There are 5-7 pairs of magnetic steel on the stator, and the number of slots in the rotor armature is 39-57. Since the armature winding is fixed in the wheel housing, the heat is easily dissipated with the help of the rotating housing. The rotating shell is woven with 36 spokes, which is more conducive to heat conduction. The micro-signal of Jicheng training is worthy of your attention!

What are the characteristics of brushed and toothed motors?

Answer: Because there are brushes in the brushed motor, the main hidden danger is "brush wear". Users should notice that there are two types of brushed motors: toothed and non-toothed. 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, the motor speed should be at 170 rpm/about). Since the high-speed motor is decelerated by gears, it is characterized in that the rider feels strong power when starting, and has strong climbing ability. However, the electric 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 is also mechanically worn. Insufficient lubrication will lead to increased gear wear, increased noise, and low current during use. Increase, affecting motor and battery life.

What is a brushless motor?

Since the controller provides direct current with different current directions to achieve the alternating change of the coil current direction in the motor. There are no brushes and commutators between the rotor and stator of brushless motors.

How does the motor commutate?

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 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: In the three-phase circuit of the brushless motor or brushless controller, one phase cannot work. Phase loss is divided into main phase loss and Hall phase loss. The performance is that the motor shakes and cannot work, or the rotation is weak and the noise is loud. It is easy to burn out if the controller works in the state of lack of phase.

What are the common types of motors?

Answer: Common motors include: hub motor with brush and gear, hub motor with brush and no gear, brushless hub motor with gear, brushless hub motor without gear, side-mounted motor, etc.

How to distinguish high and low speed motors from the type of motor?

Answer: A brushed and geared hub motors, brushless geared hub motors are high-speed motors; B brushed and gearless hub motors, brushless and 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 the power of the motor?

Answer: The selection of the rated power of the motor is a very important and complicated issue. When the load is on, if the rated power of the motor is too large, the motor is often in light-load operation, 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". If the motor current exceeds the rated current, the internal loss of the motor will increase. When the efficiency is low, it is a small matter, and the most 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 it may not be able to drag the load at all, which will cause the motor to be in the starting state for a long time and be overheated and damaged. Therefore, the rated power of the motor should be selected strictly according to the operation of the electric vehicle.

Why do general DC brushless motors have three Halls?

Answer: Briefly speaking, in order for the brushless DC motor to rotate, there must always be 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 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 magnetic field direction of the stator coil must change to a certain extent. So how do you know to change the direction of the stator magnetic field? That depends on the three Halls. Think of those three Halls as having the task of telling the controller when to change the direction of the current.

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

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

Generally, at what temperature can the motor work normally? What is the maximum temperature the motor can withstand?

Answer: If the measured 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 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, causing the coil to short circuit. When the coil temperature is above 150 degrees, the temperature of the motor shell is about 100 degrees, so if the shell temperature is used as the basis, 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 be less than 20 degrees Celsius higher than the ambient temperature, but what is the reason for the motor to heat more than 20 degrees Celsius?

Answer: The direct cause of the motor heating is due to the large current. Generally, it may be caused by short circuit or open circuit of the coil, demagnetization of the magnetic steel, or low efficiency of the motor. 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 power loss in the motor, which will eventually turn into heat energy, which will increase the temperature of the motor and exceed the ambient temperature. The value by which the motor temperature rises above the ambient temperature is called warm-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 does not increase, but maintains a stable temperature, that is, it is in a state of balance between heat generation and heat dissipation.

Generally, what is the allowable temperature rise? Which part of the motor is the most affected by the temperature rise of the motor? How is it defined?

Answer: When the motor is running under load, it is better to give full play to its role, that is, the higher the output power of the load, the better (if 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 temperature-resistant 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 aspects of insulating materials are very stable, and their working life is generally about 20 years. Beyond this limit, the life of the insulating material will be shortened sharply, or even burnt. 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.