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.