These are electrical devices that use electrical energy and fluctuating magnetic fields that interact with each other to make a coil and consequently the armature rotate over and over and over and over and over and over and over and over ...
The fundamental difference between an AC motor vs a DC motor (like the one you built in your lab) is the type of commutator.
In a AC motor, the electricity moves back and forth rapidly. This causes the magenetic field in the coil to flip.
In a DC motor, the electrons flow from the negative terminal to the positive terminal of the battery. In order to ensure that the magnetic field will "flip," a split ring commutator is used. This allows the coil to continue turning in the same direction and not get "hung up."
