An electric motor works by using magnets along with coils of wire to transfer electric energy into kinetic energy. The coil is positioned between two magnetic poles; when current passes through the coil, it experiences force in opposite directions caused by the poles of the magnet, and this causes movement.
The basic principle of an electric motor is that an electric current that is placed in a magnetic field will experience force. This is what is created and harnessed in an electric motor.
The coil is used to carry the current and is usually bent into a loop. This goes past the magnetic field. When it does it experiences force in opposite directions. These opposing forces create a turning movement to rotate the coil. This is otherwise known as torque.
To make the turn, the direction of the current must be changed every half turn. If this were not so, the coil would stop turning because unlike magnetic poles attract each other. When the current is changed, the poles also change, which in turn makes the coil turn.
To increase the efficiency of an electric motor in practical applications they typically have several loops on an armature. This increases the effect of the magnetic field. Also, the higher the voltage of electricity, and the stronger the magnetic field, the more torque will be produced.