Your question is a bit confusing as stated but I will try to answer what you seem to be asking.
An electric motor can be powered by either AC voltage or DC voltage. It depends upon the design. The motor is basically a coil of wire turning inside a magnet or a magnet turning inside a coil. When current runs through the coil it produces its own magnetic field. The two magnets interact and try to line up, just as a compass needle and a bar magnet will try to align themselves.
The "trick" is to have either the coil or the magnet spin fast enough so that once alignment happens it keeps spinning. Whichever part is spinning must now turn a full 360 degrees to realign itself. If this is done right it happens over and over again which causes a shaft to turn with it. There's your motor.
In an AC motor the alternating current naturally keeps the motor spinning it is in synch with the turning motor. In a DC motor you need to artificially alternate the current by a switch on the shaft called a "governor".
You need enough voltage to keep it going. A big motor has heavy parts to keep moving and so needs a lot of voltage to sustain it. 12 volts DC may not be enough to keep it going.