In electric motors we have two main parts, one fixed, which does not move when it starts, and another movable, which revolves around an axis when the motor is turned on. The fixed part is made of copper wires, covered with a transparent material forming two coils. Already in the part fixed to the axis, the copper wires are rolled around the axis. When we observe the moving part of a blender motor it shows that it also has, coupled to the shaft a metal cylinder, formed of small copper plates, separated from each other by grooves, whose function is to electrically isolate one plate from the other.
The electric circuit of the moving part is composed of several pieces of independent copper wire where the wire is covered by a transparent insulating material and its ends are attached to the copper plates. This piece of cylindrical shape coupled to the shaft is called a collector ring, and two small coals slide on the plates. When the electric motor is put into operation, there is an electric current in the fixed coils and also in the electric circuit fixed to the axis and in contact with the coals.