Brushless motors are technically a type of synchronous AC motor, but they are called "brushless DC" because they are powered by a DC power source. An electronic controller takes the DC power and converts it into a three-phase AC current to drive the motor.  

• DC power input: A battery or other DC power source supplies the motor. 

• Electronic controller: The controller is essential for operation. It acts as a replacement for the mechanical brushes and commutator in a traditional brushed motor. 

  AC switching: The controller switches the DC voltage on and off, sending it to the motor's coils in a sequence that simulates a three-phase AC current. This creates the rotating magnetic field necessary to turn the rotor. 

• Because of this design, brushless motors are a hybrid of AC and DC motor principles, but the term "brushless DC" is used to emphasize that they are designed to operate with a DC power source and an electronic controller.  

So, the name "Brushless DC" highlights the two most important user-facing features: it runs on DC power and operates without brushes. It's a hybrid technology that combines AC motor principles with DC power convenience.