Electronic Speed control (ESC) systems for brushed motors are often very different by design. This explains the fact that brushed ESCs aren’t compatible with brushless motors. Brushless speed control systems are basically for driving tri-phase brushless motors. It does this by sending a series of signals for rotation. The correct phase often varies with rotation of the motor. This rotation is take into account by ESC. The controller generates the signal depending on the back EMF signal it receives from the motor. The EMF signal guides the controller on the position of the rotor and what fets to switch on.
Brushless motors, also known as inrunners or outrunners, have become very common with radio-controlled airplane hobbyists because of their high level of efficiency, longevity, power and light weight compared to traditional brushed motors. Brushless motor controllers are however much more complex than their brushed counterparts.
Brushless speed control systems are way more efficient than the brushed counterparts because, apart from the ball bearings on which the rotor spins, there isn’t any physical connection whatsoever, automatically making brushless motor more efficient and long lasting because no friction takes place on the brushes and commutator. Using a computer-programmable speed controls to control the rotation of the rotor vastly increases efficiency.
With burshless speed control system, there is completely no sparking from brushes on commutators as experienced in brushed control systems, and so electric interference is kept to the minimum. The coils in burshless speed control motors are much easier to get cool, hence boosting efficiency even further.
The only possible limitation to brushless speed control system is its increased starting cost usually because of the high power consumption. But the fact there won’t be motor brushes and brush springs for you to replace also reduces the eventual overall cost considerably. You won’t be replacing armatures or even the whole motor ever.