Question

To transform electrical energy into mechanical energy, the electromagnet in a

motor must rotate in just one direction. What allows this consistent rotation
to occur?

Answer 1

Motors commonly contain a "commutator" which allows a magnetic field due to a loop of wire to always be in a say "clockwise or counterclockwise" direction even tho the loop of wire is rotating.

That means that magnetic field due to the surrounding magnets is always in the same direction, but the magnetic field due to the rotating loop of wire is continually changing so that it will always oppose the surrounding field which remains in a constant direction.

This is most easily seen in a "DC - direct current motor".