MotorsQuestion 1212 of 1506

A motor is driven by square-wave current from Hall sensors. What is it called?

  1. A true synchronous AC motor
  2. A wound rotor motor
  3. A brushless DC motor
  4. A shaded pole motor
Show answer

Correct answer: A brushless DC motor

Square-wave drive from simple Hall sensors makes it a brushless DC motor. True synchronous motors use sine waves.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 13.2: Synchronous Motors

Practice motors

Questions last reviewed: 18 October 2026