Basic Concept of Brushless Motor

According to the structure and working principle of the motor, we can categorize the motor into brushed motor, inner rotor brushless motor and outer rotor brushless motor.

Brushed motor: we also call it DC motor or carbon brush motor, it is the oldest type of motor and the most numerous type of motor at present. When the motor works, the coil and commutator rotate, the magnets and carbon brushes do not rotate, and the alternating direction of the coil current is accomplished by the phase changer and brushes that rotate with the motor. This kind of motor has the advantages of relatively low cost, high torque, simple structure and easy maintenance.
However, due to structural limitations, so the disadvantages are also more obvious:
1, mechanical commutation sparks caused by commutator and brush friction, electromagnetic interference, noise, short life.

2, complex structure, poor reliability, faults, the need for frequent maintenance.
3, due to the existence of commutator, limiting the rotor inertia further down, affecting the dynamic performance. Therefore, in the mold world is mainly used in the slower speed and not sensitive to vibration of the car model, boat model above, aviation model rarely use brush motor.
Brushless motor: this is a kind of motor used most in the mold world except brush motor, brushless DC motor does not use mechanical brush device, using square wave self-control permanent magnet synchronous motor, replacing the carbon brush commutator with Hall sensor, using neodymium-iron-boron as the permanent magnet material of the rotor, the performance has a great advantage compared with the general traditional DC motor. With high efficiency, low energy consumption, low noise, long life, high reliability, servo control, stepless frequency control and other advantages, as for the shortcomings of …… is more expensive than the brush, not good maintenance, widely used in aeromodelling, high-speed car models and boat models.
However, a single brushless motor is not a complete power system, brushless basic must be through the brushless controller is also the control of the ESC in order to achieve continuous operation. While ordinary carbon brush motors rotate windings, brushless motors rotate magnets regardless of whether they have an outer or inner rotor structure. So any motor is composed of stator and rotor together.
The stator of the brushless motor is the part that generates the rotating magnetic field, which can support the rotor to rotate, and it is mainly composed of silicon steel sheet, enameled wire, bearings, and support parts; while the rotor is the part that glues the neodymium-iron-boron magnets to rotate in the action of the rotating magnetic field of the stator, and it is mainly composed of rotor shaft, magnets, and support parts. In addition, the number of magnetic pole pairs composed of stator and rotor also affects the speed and torque of the motor.