First, the principle of a brush motor
　　The brush motor adopts mechanical commutation, the magnetic pole does not move, and the coil rotates. When the motor is working, the coil and the commutator rotate, the magnet and the carbon brush do not rotate, and the alternation of the direction of the coil current is accomplished by the commutator and the brush that the motor rotates.
　　In brushed motors, this process consists of arranging the two power input terminals of each group of coils into a ring, which are separated from each other by insulating materials to form a cylinder-like thing that is integrated with the motor shaft. A small column (carbon brush) made of two carbon elements presses two points on the ring cylinder's power input ring at two specific fixed positions under spring pressure to energize one set of coils.
　　As the motor rotates, different coils or different two poles of the same coil are energized at different times so that the NS pole of the coil generating a magnetic field and the NS pole of the nearest permanent magnet stator have a suitable angle difference, magnetic field anisotropic attraction, and the same sex Repulse, generate power, push the motor to rotate. The carbon electrode slides on the coil terminal, like a brush on the surface of the object, so it is called a carbon “brush”.
　　Sliding each other will rub the carbon brush and cause loss. The carbon brush needs to be replaced on a regular basis. The carbon brush and the coil connection will alternately open and close, sparks will occur, electromagnetic breakdown will occur, and electronic equipment will be disturbed.
　　Second, the principle of brushless motor
　　The brushless motor adopts electronic commutation, the coil does not move, and the magnetic pole rotates. The brushless motor uses a set of electronic equipment to sense the position of the permanent magnet pole through the Hall element. According to this perception, the electronic circuit is used to timely switch the direction of the current in the coil to ensure that the magnetic force in the correct direction is generated to drive the motor. . Eliminates the shortcomings of brushed motors.
　　These circuits are motor controllers. The controller of the brushless motor can also realize some functions that can not be realized by the brush motor, such as adjusting the power switching angle, braking the motor, reversing the motor, locking the motor, using the brake signal, and stopping the power supply to the motor. The electronic alarm lock of the battery car now fully utilizes these functions.
　　The brushless DC motor consists of a motor body and a driver and is a typical electromechanical integration product. Since the brushless DC motor is operated autonomously, it does not add starter windings on the rotor like a synchronous motor with heavy-duty start under heavy-duty speed regulation, nor does it cause oscillation and out-of-step when the load suddenly changes.
　　Third, the difference between speed
　　In fact, the control of the two motors is voltage regulation, only because the brushless DC uses electronic commutation, so digital control can be achieved, while brushed DC is commutated by carbon brush, using thyristor, etc. Traditional analog circuits can be controlled and are relatively simple.
　　1. The brush motor speed regulation process is to adjust the voltage of the motor power supply voltage. The adjusted voltage and current are converted by the commutator and brush to change the strength of the magnetic field generated by the electrode and achieve the purpose of changing the rotation speed. This process is called variable speed control.
　　2. The brushless motor speed regulation process is that the voltage of the power supply of the motor is constant, the control signal of the ESC is changed, and the switching speed of the high-power MOS tube is changed by the microprocessor to realize the change of the rotation speed. This process is called variable frequency speed regulation.
　　Fourth, the performance difference
　　1. The brush motor has a simple structure, long development time and mature technology.
　　As early as the nineteenth century when the motor was born, the resulting practical motor was the brushless version, namely the AC squirrel-cage asynchronous motor, which was widely used after the generation of alternating current. However, asynchronous motors have many disadvantages that cannot be overcome, resulting in slow development of motor technology. In particular, DC brushless motors have not been able to be put into commercial operations. With the rapid development of electronic technology, it has only been gradually put into commercial operation in recent years. In essence, it still belongs to the category of AC motors.
　　Shortly after the birth of brushless motors, people invented DC brush motors. Due to the simple structure of DC brush motor, easy production and processing, easy maintenance, and easy control; DC motor also has the characteristics of fast response, large starting torque and ability to provide rated torque from zero speed to rated speed. It has been widely used.
　　2, DC brush motor response speed, starting torque
　　The brushed DC motor has a quick start response speed, a large starting torque, a smooth shifting speed, almost no vibration from the zero speed to the maximum speed, and a greater load during starting. The brushless motor has a large starting resistance (inductive reactance), so the power factor is small, the starting torque is relatively small, there is a squeaking noise at the start, and accompanied by a strong vibration, the starting load is small.
　　3, DC brush motor running smoothly, starting and braking effect is good
　　The brush motor regulates pressure and speed, so the starting and braking are stable, and the constant speed operation is also stable. The brushless motor is usually digital frequency conversion control. First, the alternating current is converted into direct current, and the direct current becomes alternating current. The speed is controlled by the frequency change. Therefore, the brushless motor runs unevenly during starting and braking, and the vibration is large, only when the speed is constant. Will be stable.
　　4, DC brush motor control accuracy is high
　　The DC brush motor is usually used together with a gear box and a decoder to make the motor output power higher, control accuracy is higher, the control accuracy can reach 0.01 mm, and almost all the moving parts can be stopped at any desired place. All precision machine tools use DC motor control accuracy. Since the brushless motor is not stable during starting and braking, the moving parts are stopped at different positions each time, and must be stopped by the positioning pin or the stopper to the desired position.
　　5, DC brush motor is low in cost and easy to maintain. Because the DC brush motor has a simple structure, low production cost, many manufacturers, and mature technology, it is also widely used, such as factories, machine tools, precision instruments, etc. If the motor is faulty, just replace the carbon brush, each The carbon brush only costs a few yuan and is very cheap. The brushless motor technology is immature, the price is high, and the application range is limited. It should be mainly on constant speed equipment, such as inverter air conditioners, refrigerators, etc. The brushless motor can only be replaced.
　　6, no brush, low interference
　　The brushless motor removes the brush, and the most direct change is that there is no spark generated when the brush motor is running, which greatly reduces the interference of the spark to the remote control radio.
　　7, low noise, smooth operation
　　The brushless motor has no brush, friction is greatly reduced during operation, and the operation is smooth and the noise is much lower. This advantage is a great support for the stability of the model operation.
　　8, long life, low maintenance costs
　　With fewer brushes, the wear of the brushless motor is mainly on the bearing. From the mechanical point of view, the brushless motor is almost a kind of maintenance-free motor. If necessary, only some dust removal and maintenance can be done.