Quote Originally Posted by fkirons View Post
if the motor has a an Electronic Speed Control its noticeable. and you need the room in the machine for the circuit even if the circuit is attached to the motor (like some of the high end Maxons for ex). If you have just two terminals then most likely doesn't have ESC.
Take a look at some Helicopter and car racing motors.
not always, look at the motors on computer fans there esc is built inside and you cant see it from outside, there are few things that i havnt took apart lol