How does the commutation takes place in a brushless motor?
In the stator using electronic switching or By magnetic coupling in the rotor.
I have the first choice as my answer but I'm just double checking does anyone have an idea? thanks...
How does the commutation takes place in a brushless motor?
There is no "commutation" in a brushless motor.
Commutation refers to the energy passing to the rotating part of the motor (the armature or rotor) via slip rings or a segmented set of conductors and brushes.
Is the stator using electronic switching or by magnetic coupling in the rotor. Both answers are correct.
For a DC brushless motor the stator of "field" is switched electronically
For an AC brushless motor such as a squirrel-cage motor, the coupling to the rotor is by magnetic coupling and this coupling produces a current in a few turns on the rotor. The magnetic field produced by the rotor reacts with the outer field to produce rotation.
There is commutation, it's just not mechanical. I was using the word "commutation" in the generic sense of a circuit that periodically switches the current into the motor (stator or rotor as the case may be) to provide a rotating field. Brushless DC motors are also called "electronically commutated" so that is not an incorrect definition.