title_body: Why do brushless motors have 3 wires compared to 2 wires on a brushed motor? I'm familiar with regular DC motors, which is what brushed motors appear to be. They have fixed stator magnets, rotor coils connected to the shaft and two brushes that power the coils at the right time via a commutator. By varying the amount of power via the two leads connected to the brushes I can vary the speed the motor spins at (more or less).
  
  Yet brushless motors typically have 3 input wires. I can see an arrangement of coils and magnets still, but why does it need 3 wires and a special ESC to drive it?
upvoted_answer: A standard brushed motor has a positive, negative and a commutator that switches the polarity of the rotor.
  
  Conversely, a brushless motor has a multiple of three sets of coils. These coils are energized in a particular order to create a series of electromagnetic forces that ‘pull’ the bell (which contains permanent magnets) around.
  
  As there are three sets of coils, there are three wires - one for each set of coils so they can be individually energized.
  
  The ESC is what controls the sequence in which the coils are energized.