Construction
(i) Armature: The rotating part of the motor, including the electromagnets, is called the armature. Basically it consists of a large number of turns of insulated copper wire wounded over a soft iron core.
(ii) Field Magnet: Armature coil is placed between the North and South poles of two permanent magnets which produces a strong magnetic field.
(iii) Split ring or commutator: The wires from each of the three coils are attached to three metal plates called commutator at the end of armature. In the DC motor, the two halves of a metallic ring R1 and R2 are connected with the two ends of armature coil. They work as commutator. These rotate with the coil and reverse the direction of current flowing through the coil every time the coil just passes the vertical position during a revolution.
(iv) Carbon brushes: There are two flexible carbon brushes Bi and B2 which are so fixed that when the rotor spins, the three plates come into contact with the positive and negative brushes. Electric current flows through the brushes into the coils.
(v) Battery: It is connected across the brushes.
