The "BL" in BLDC motor means "brushless", which means that the "brush" in the DC motor (brush motor) is gone. The role of the brush in the DC motor (brush motor) is to energize the coil in the rotor through the commutator. So how does the brushless BLDC motor energize the coil in the rotor? It turns out that the BLDC motor uses permanent magnets as the rotor, and there are no coils in the rotor. Since there are no coils in the rotor, there is no need for a commutator and brushes for energizing. Instead, there are coils as stators. The operation diagram of the BLDC motor is shown below.
The magnetic field created by the fixed permanent magnet in the DC motor (brush motor) does not move, and it rotates by controlling the magnetic field generated by the coil (rotor) inside it. The number of rotations is changed by changing the voltage. The rotor of the BLDC motor is a permanent magnet, and the rotor rotates by changing the direction of the magnetic field generated by the surrounding coils. The rotation of the rotor is controlled by controlling the direction and magnitude of the current passing to the coil.
BLDC motors use permanent magnets as rotors. Since there is no need to supply power to the rotor, brushes and commutators are not required. The power supplied to the coils is controlled externally.
