Basic knowledge of electric bicycle motors

1. What is a motor?

A: A motor is a component that converts battery power into mechanical energy that drives the wheels of electric vehicles.

2. What is a stator?

Answer: The part that does not rotate 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 inner stator motor.

3. What is a rotor?

Answer: The rotating part of a brush or brushless motor. The hub type brushed or brushless toothless motor is called the rotor, this kind of motor can be called outer rotor motor.

4, what is carbon brush?

A: There are brush motors inside the top of the commutator. When the motor rotates, electric energy is sent to the coil through the commutator. Because its main component is carbon, called carbon brush, it is easy to wear. Maintenance should be regularly maintained and cleaned up.

5. What is a brush holder?

Answer: Mechanical guides for holding and holding carbon brushes inside a brush motor.

6. What is a commutator?

A: Inside the brush motor, there are strips of metal surfaces that are insulated from each other. When the motor rotor rotates, the strips of metal alternately touch the positive and negative poles of the brush to realize the positive and negative alternation of the motor coil current direction, completing the brush motor coil. The commutation.

7, what is the phase sequence?

Answer: The order of brushless motor coils.

8, what is magnetic steel?

A: Generally used for magnetic materials with high magnetic field strength, NdFeB magnets are used for electric motor.

9, what is a brush motor?

Answer: When the motor works, the coil and commutator rotate, and the magnet and carbon brush do not rotate. The alternation of the direction of the coil current is accomplished by the commutator and the brush rotating along with the motor. In the electric vehicle industry, brush motors are divided into high-speed brush motors and low-speed brush motors. There are many differences between the brush motor and the brushless motor. It can be seen from the name that the brush motor has a carbon brush and the brushless motor does not have a carbon brush.

10. What is a brushless motor?

A: The controller provides DC currents in different current directions to alternate the direction of the coil current in the motor. There is no brush or commutator between the rotor and the stator of the brushless motor.

11. How to realize motor commutation?

Answer: When the brushless or brushed motor rotates, the energizing direction of the coil in the motor needs to be alternately changed so as to achieve continuous rotation of the motor. The commutation of the brush motor is accomplished by a commutator and a brush together, and the brushless motor is completed by the controller.

12. What is the missing phase?

Answer: In the three-phase circuit of brushless motor or brushless controller, one phase cannot work. The missing phase divides the main phase and the Hall phase. The performance is that the motor shake can not work, or the rotation is weak and the noise is large. The controller is very easy to burn in the absence of phase.

13. What are the common types of motors?

Answer: Common motors include: brushed hub motor, brushless hub motor, brushless hubless motor, brushless hub motor, and side-mounted motor.

14, how to distinguish from the type of motor is high and low speed motor?

Answer: A brushed hub motor and brushless hub motor belong to high-speed motor;

B brushless hub motor, brushless hubless motor belongs to low speed motor.

15. How is the efficiency of the motor defined?

A: The efficiency of the motor refers to the ratio of the mechanical energy output by the motor to the power provided by the power supply. It is represented by the letter "ã‚Š".

16. How is the brushless motor classified?

A: From the phase angle can be divided into two broad categories, namely brushless motor is divided into 60 ° and 120 ° phase angle; according to the speed points, can be divided into high-speed brushless motor and low speed brushless motor; press the motor has The position sensor is divided into two parts: a position sensor brushless motor and a position sensorless brushless motor.

17. What is a sensorless brushless motor?

Answer: For the sensorless brushless motor, the vehicle pedal must be lifted first. After the motor has a certain rotation speed, the controller can recognize the phase of the brushless motor, and then the controller can supply power to the motor. Because it can not achieve zero-speed start, it is rarely used. But because there are no sensors, all of them have one point of failure, and their cost is lower.

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

A: The power consumption of the Hall-effect brushless motor ranges from 6mA to 20mA.

19, brushless motor Hall voltage range is how much?

A: The voltage range of the brushless motor Hall is generally 3-24V.

20, the general motor at normal temperature? How high can the motor withstand high temperatures?

Answer: If the temperature of the motor cover exceeds 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 less than 20 degrees. In general, the motor coil is made by winding an enameled wire. When the temperature of the enameled wire is higher than 150 degrees, the paint film will fall off due to excessive temperature, resulting in a short circuit in the coil. When the coil temperature is 150 degrees or more, the motor housing exhibits a temperature of about 100 degrees, so if it is based on its case temperature, the maximum temperature that the motor can withstand is about 100 degrees.

21, the temperature rise of the motor should be below 20 °C, that is, the temperature of the motor end cover exceeds the ambient temperature should be less than 20 °C, but the reason why the motor heat over 20 °C?

A: The direct cause of motor heating is due to large currents. It may be caused by short circuit or open circuit of the coil, low efficiency of the motor in demagnetization of the magnet steel, and the normal condition is that the motor runs for a long time with large current.

22. How to measure the phase angle of a brushless motor?

Answer: When the controller is powered on and the controller supplies power to the Hall element, the phase angle of the brushless motor can be detected. The method is as follows: Use the multimeter's +20V DC voltage range, connect the red meter to the +5V line, and measure the high and low voltage of each of the three leads with a black meter (there is a skill in the use of red and black meter leads). Press the 60° and 120° motors. The commutation table can be controlled.

23. What if a 60° brushless controller is used on a 120° brushless motor? What about the other way?

A: It will lead to the phenomenon of lack of phase and can't work normally. However, an intelligent brushless controller developed by Tianjin Songzheng Technology can automatically identify 60° motor or 120° motor, which can be compatible with two kinds of motors and make maintenance and replacement. much easier.

24. What is the intuitive difference between brushed high speed motor and brushed low speed motor?

Answer: A. High-speed motors have overrunning clutches (functions like flywheels), making it easier to move in one direction and effortlessly in the other direction; low-speed motors are equally easy to turn in both directions.

B. The noise of the high-speed motor when the vehicle is rotating is relatively large, and the low-speed motor has less noise. Experienced people can easily identify with their ears.

25. How is the starting current of the motor defined?

A: Generally, the starting current of the motor must not exceed 2 to 5 times of its rated current. This is an important reason why current limiting protection is performed on the controller.

26. Why are the motor speeds on the market getting higher and higher and what is the impact?

Answer: A. The supplier can speed up the cost reduction. It is also a low-speed motor. The number of turns of the coil with high speed is lower, and the number of silicon steel plates and magnets is also reduced. The buyer thinks that the speed is high.
B. When the rated speed is working, the efficiency is not changed, but the efficiency is obviously low in the low-speed area, that is, the start-up is weak.

C. Inefficient, need to start with a large current, riding current is also large, the current limit of the controller is large, the battery is not good.

27. How to repair abnormal motor fever?

A: The maintenance method is generally to replace the motor or perform maintenance.

28. When the no-load current of the motor is greater than the limit data of the reference table, it indicates that the motor has failed. What are the causes? How to repair?

Answer: The internal mechanical friction of the motor is large; the coil is partially short-circuited; the magnet demagnetizes; the DC motor commutator deposits carbon. The maintenance method is generally to replace the motor, or replace the carbon brush and clean up the carbon deposit.

29. What is the maximum fault-free maximum load current of various motors?

A: Motor rated voltage of 24V rated voltage of 36V side-hanging 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 0.6A

Low speed brushless motor 1.0A 0.6A