i) Yoke: The yoke serves the following two purposes. i) It supports the other components such as poles and provides mechanical protection for whole machine. ii) It forms a part of the magnetic circuit & provides the path of low reluctance for the magnetic flux.
ii) Pole: The pole shoe serves two purposes i) They spread out flux in the air gap & their large cross section reduces the reluctance of the magnetic path ii) They support the exciting coils or field coils.
iii) Field winding: For excitation of poles
iv) Commutator: The function of the commutator is to reverse the current in each conductor of the armature as it passes from one pole to another and thus to help the motor to develop a continuous and unidirectional torque