title_body: Why do brushless motors have 3 wires compared to 2 wires on a brushed motor?
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.