Features of brushless motors

The brushless motor is the main driving part of the e-bike, the heart of the e-bike. The motor directly affects the performance of the electric bicycle.

According to industry experts, there are two main types of motors used in domestic electric bicycles: brush motors and brushless motors; brush motors are also available in high and low speeds.

Brushed low-speed motors are used by electric bicycles, also known as brushless gearless motors, which have a higher current and weaker performance when starting and climbing an electric bicycle, and are generally rarely used by manufacturers.

Brushed high speed motors (3600 rpm or so), which use carbon brushes as the two contacts of the motor power supply, are controlled by a speed control handle and controller, and the secondary gear reduction and overrunning clutch are used to achieve an infinitely variable speed of 0-20 km/h for electric bicycles.

The brushed high-speed motor currently used has a high gold content, strong motor reduction gears, good wear resistance and reasonable design, so the return rate is low; and the cost of repairing and replacing the gears and motor is low, effectively reducing the maintenance costs of electric bicycles; and the brushed motor can be easily ridden by human power through the overrunning clutch and flywheel.

Brushless motors are currently used by e-bike manufacturers are generally brushless and gearless motors. Its speed control system is more costly than that of a brush high-speed motor, and the controller is prone to failure in use. An electric bicycle fitted with a brushless motor must travel at a speed of 35 km/h or more in order to work at its optimum efficiency.

How to choose brushless motor and brush motor in daily work, let me compare their characteristics below:

1. The brushless motor is mainly composed of stator and rotor, while the brushless motor is mainly composed of stator, rotor, carbon brush, commutator and so on. The brushless motor has no friction between the carbon brush and the commutator, the friction is small, and the power consumption is small. The brushed motor has friction between the carbon brush and the commutator, the friction is large, and the power consumption is large.

2. The brushless motors has no frictional heating between the carbon brush and the commutator, with low heating and long service life. The brush motor has the friction heat between the carbon brush and the commutator, which is larger than the brushless motor and shortens the life.

3. Since the brushless motors does not have carbon brushes and commutators, it has low friction, low heat generation, improved efficiency, energy saving and emission reduction. Due to the carbon brushes and commutator, the brushed motor has high friction, high heat generation, low efficiency and waste of energy.

4. Since carbon brushes need to be replaced regularly, it is difficult to clean the carbon brushes against dust, which is laborious and laborious. The brush motor wastes manpower and material resources. On the contrary, the brushless motor saves manpower and material resources.

5. The brushless motors has no carbon brushes, and there is no electric spark generated when the carbon brushes are running, which reduces the interference to the outside world.

6. The brushless motors has no carbon brushes, and the noise generated during operation is low, and at the same time, it is possible for the motor to achieve high speed.

The high-speed motor is slightly more expensive because its armature winding resistance is small, while the low-speed motor has a larger resistance. Therefore, the high-speed motor consumes less current during driving. I suggest that I buy a high-speed motor.

In the previous market, three types of motors are more common: brushed high-speed motors, brushed low-speed motors, and brushless low-speed motors. The motor is what we often say. The high-speed motor has high power and high speed (under normal driving, high-speed motor 3000 rpm, low-speed motor 500 rpm), it needs to be decelerated by a reduction gear device to output large torque power, so its noise is higher than that of low-speed motor The noise is relatively loud.

However, the advantages of high-speed motor vehicles can be shown under overloading or climbing road conditions. Because of these advantages, high-speed motors have more complicated production processes and relatively higher costs than low-speed motors, so the price is slightly more expensive.

We should pay more attention to our daily car purchases. Don’t assume that there is no wear and tear because the motor is silent, and the car will be in good condition. You must know that the main indicators of a motor are motor efficiency and power. The biggest weakness of low-speed motors is the motor’s low efficiency, heavy weight, poor power, weak riding, and high power consumption.

Because the brushed high-speed motor has a high speed (3000 rpm for high-speed motor and 500 rpm for low-speed motor), it needs to be decelerated by a reduction gear device to output large torque power, so its noise is relatively larger than that of low-speed motors. The production process of high-speed motors is more complicated than low-speed motors, and the cost is high. The price is about 200 yuan more expensive. Like some famous brand electric vehicles, high-speed motors are often used.

High-speed motor: The relative rotation speed of the stator and the rotor of the high-speed motor is fast, the back electromotive force generated is high, the working current is limited in the winding, the current consumption is small, and it is relatively power-saving.

Low-speed motor: On the contrary, the low-speed motor has a low relative speed, low back electromotive force, low current limit ability, large current consumption, and waste of electricity. This phenomenon is especially obvious when running uphill and upwind. At this time, the vehicle speed is lower, the back electromotive force is almost zero, and the working current consumption is particularly large. For a battery with a small capacity, it will exceed the allowable discharge current and shorten its life.

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