What is DC brushless motor and what kind of advantages does it have?
1. The definition of brushless motor
Brushless motors, also called brushless DC motors, use semiconductor switching devices to achieve electronic commutation, that is, electronic switching devices are used to replace traditional contact commutators and brushes. It has the advantages of high reliability, no reversing sparks, low mechanical noise, etc., and is widely used in high-end audio jacks, video recorders, electronic instruments and automated office equipment.
2. Analysis of brushless motor structure
In terms of structure, brushless motors and brushed motors have similarities. There are also rotors and stators, but the structure is opposite to that of brushed motors. The rotor of brushed motors is a coil winding connected to the power output shaft, and the stator is a permanent magnet. Steel; The rotor of the brushless motor is permanent magnet steel, which is connected with the output shaft together with the casing. The stator is a winding coil. The commutation brush used by the brush motor to alternately transform the electromagnetic field is removed, so it is called a brushless motor. Now there is a problem. Without the transformation of the electromagnetic field, how to make the brushless motor rotate?
3. Operating principle of brushless motor
Simply put, by changing the alternating frequency and waveform of the current wave input to the stator coil of the brushless motor, a magnetic field is formed around the winding coil to rotate around the geometric axis of the motor. This magnetic field drives the permanent magnet on the rotor to rotate. The motor starts to rotate. The performance of the motor is related to the number of magnets, the strength of the magnetic flux, and the input voltage of the motor. It also has a lot to do with the control performance of the brushless motor, because the input is direct current, and the current needs electronics. The governor turns it into a 3-phase alternating current, and it also needs to receive a control signal from the remote control receiver to control the speed of the motor to meet the needs of the model. In general, the structure of the brushless motor is relatively simple, and the real decision of its performance is the brushless electronic speed controller. A good electronic speed controller requires a single-chip control program design, circuit design, complex processing technology and other processes. The overall control, so the price is much higher than the brush motor.
4. Comparison of advantages and disadvantages of brushless motor and brush motor
Disadvantages of brushed motors
1. Large friction and large loss
Old model friends have encountered this problem when playing with brushed motors before. After using the motor for a period of time, the motor needs to be opened to clean the carbon brushes of the motor, which is time-consuming and laborious, and the maintenance intensity is no less than a home cleaning.
2. High heat generation and short life span
Due to the structure of the brush motor, the contact resistance between the brush and the commutator is very large, which causes the overall resistance of the motor to be large and easy to generate heat. The permanent magnet is a thermal element. If the temperature is too high, the magnet will demagnetize , The performance of the motor is reduced, and the life of the brushed motor is affected.
3. Low efficiency and low output power
The heat problem of the brushed motor mentioned above is largely due to the fact that the current is done on the internal resistance of the motor, so the electrical energy is converted to heat to a large extent, so the output power of the brushed motor is not high and the efficiency is not high.
Brushless motor advantages
1. No brush, low interference
The brushless motor removes the brush, and the most direct change is that there is no electric spark generated when the brush motor is running, which greatly reduces the interference of electric sparks to remote control radio equipment.
2. Low noise and smooth operation
The brushless motor has no brush, the friction is greatly reduced during operation, the operation is smooth, and the noise is much lower. This advantage is a huge support for the stability of the model.
3. Long life and low maintenance cost
Without the brush, the wear of the brushless motor is mainly on the bearing. From the mechanical point of view, the brushless motor is almost a maintenance-free motor. When necessary, only need to do some dust removal maintenance. 
