Originally Posted by
jimjim1
Confusingly some motors are described as "Brushless DC motors".
They are AC motors with integrated electronics to convert the DC supply to AC for the motor.
I'm afraid that's not true. The Brushless DC motor is a very different thing (electrically and magnetically) to an AC motor. A brushless DC motor is exactly what it says on the tin - it is a permanent magnet DC motor in which the commutator switching of the armature coils has been replaces with electronic switching timed by a microprocessor-control circuit. This allos the magnets to be put on the rotor and the coils swapped to the stator, but that's incidental. They do not use sinusoidal voltages, they do not use phase-shifted field coils for the magnetic field. They apply switched DC to the stator coils that interacts with the field produced by rotating permanent magnets. They have much better low-speed torque than either AC motors or stepper motors.
PDR