8 months ago
Last edited at 9:18AM on 4/2/2013
There are many sub-classifications of both AC and DC type motors, so this question does not have a single correct answer.
One main difference between a generic DC motor and a generic AC motor is that DC motors typically have brushes (to connect the rotor winding), while AC motor usually induce a field in the rotor.
Of course there are brushless DC motors, and synchronous AC motors for which the above statement is incorrect, so a better question would narrow it down to a specific type of AC motor, and a specific type of DC motor
The main and most important difference is that a DC motor uses brushes in contact with the commutator to supply current to the armature,whereas an AC motor does not and uses electromagnetic fields to rotate the armature.
Let's simplify this. A "d. c" motor operates on direct current like a battery. An "a. c." motor operates on alternating current. It plugs into a house plug in & keeps working whereas a D C quits when the battery is dead. At 1st there was competition between the 2 systems as far as lighting a city, but the D C was too complicated.