Originally Posted by BrianG

Well, we're sorta using both. AC means alternating current, which usually refers to a voltage that goes positive and negative in reference to a neutral or ground point. So, technically, we're using "pulsed DC".

Yes, all these motors are simply 3-phase AC motors. However, in absence of a true since-wave generator, pulsed DC works fine. Besides, a variable frequency-drive ESC would be a bit larger and more complex.