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 ...

AC vs DC motors

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."