The selection of electric motor for electric FPV drone has great influence on the flight characteristics of helicopter. Small changes in the construction of a motor result in significant effects on the weight, reactivity and total power of the helicopter
Electromagnetism
The key concept behind the function of Brushless DC motor and brushless DC motor is electromagnetism. Both designs essentially use electromagnets to convert electrical energy into kinetic energy. When an electromagnet is charged, a magnetic field is produced. This temporary magnetic field interacts with a permanent magnet located inside the motor. The combination of attraction and repulsion of electromagnet or permanent magnet is transformed into the rotation of motor shaft.
What’s the difference between brushless and brush?
The principle of brushless motor and brushless motor is very similar. When the current passes through the windings of the motor, the magnets distributed inside the motor are attracted or repelled. The repetitions and attraction of the magnet are transformed into the rotation of the axis. This allows the motor to rotate the additional propeller at a very high speed to generate thrust.
Brushless motor for FPV drone
The internal operation of the brushless motor is opposite to that of the brushless FPV drone motor. In a brush motor, the stator provides a permanent magnetic field around the rotor. The rotor of a brush motor is an electromagnet affected by the surrounding stator. A pair of brushes connected to the DC power supply contacts the commutator ring at the bottom of the rotor. The commutator ring is separated, so its rotation periodically reverses the direction of the current flowing through the rotor, because its rotation reverses the polarity of the commutator. The alternating polarity of the commutator ring is transformed into the continuous rotation of the rotor.
The whole process takes place inside the motor, providing excellent protection for precision parts. Although, the efficiency of the system is reduced due to the greater thermal insulation of the internal mechanics. By reversing the polarity of the DC power input, the rotation direction of the motor can be reversed. Because of the contact between the brush and the commutator, the service life of the brush motor is greatly reduced compared with the brushless motor. In the aspect of application, the brush motor is more suitable for the micro helicopter. Its small size, light weight and simple driving technology improve the applicability of micro FPV.
Brushless FPV drone motor
As the name suggests, a brushless FPV drone motor lacks brushes. Brushless motor can be effectively divided into two independent components: rotor and stator. The stator is the central part of the rotor. The stator is composed of a network of radial electromagnets. When the current passes through the winding, these electromagnets are alternately energized or de energized to generate a temporary magnetic field. The rotor holds a set of permanent magnets which are positioned close to the semi permanent magnet stator electromagnet. The interaction of attraction and repulsion between stator magnet and rotor magnet is transformed into rotational motion. When assembled, the rotor shaft is inserted into a pair of ball bearings located in the stator to keep the linear and smooth rotation of the rotor.
Although brushless motor is driven by DC, it can not be driven directly. Instead, brushless motors are connected to control electronics, effectively eliminating the need for brushes or commutators. The life of a brushless motor is excellent because there is no physical contact between the rotor and stator. Brushless motors are also more efficient than brushless motors. Brushless motor is widely used in small and some micro multi computer applications, high power output and efficiency is the priority.
