Brushless DC motor with Brushless DC drive circuit is using a stator winding , rather than a brush DC motor rotor windings. Mechanical commutator / brush system replaced by electronic commutator ( i.e. the brushless DC drive circuit ).

The drive circuit is make the DC supply voltage switched to the motor windings. Most brushless DC motor has three windings , and adopt star connection.

Star point is connected internally , so there is only three lines extending out . The driving circuit with PWM (pulse width modulation ) application may change the average voltage to control the rotor speed.

Permanent magnets inside the rotor . The Hall sensors with 3 embedded in the stator are used to measure the angular position of the rotor . Whenever the rotor pole close to the Hall sensor, the Hall sensor will generate a high signal or a low signal to indicate the “N”pole or “S” pole turned . These signals is help the drive circuit to find best switching time of 3 windings.