CONSTRUCTION OF D.C. GENERATOR

D.C. machine consists of five parts mainly  1.field system  2.armature core  3.armature winding  4.commutator  5.brushes 

1. Field system:- 

• The object of the field system is to produce uniform magnetic field ,within which the armature rotates.
• It consists of a number of salient poles bolted to the inside of circular frame. 
• The yoke is made of solid cast steel whereas the pole pieces are composed of stacked lamination.
  

2. Armature core:- 

• It is a rotating part of a D.C. machine and is built up in a cylindrical or drum shape.
• The goal of armature is to rotate the conductors in the uniform magnetic field.
• It consists of slotted soft-iron laminations that are stacked to from a cylindrical core .

3. Armature winding:- 

• The slots of  the armature core hold insulated conductors that are connected in a suitable manner. This is known as armature winding.
• The armature conductor are connected in series-parallel.
• The conductors being connected in series so as to increase the voltage.
• The conductors being connected in parallel path so as to increase the current.

4. Commutator:- 

• A commutator is a mechanical rectifier.
• It converts the alternating voltage generated in the armature winding into direct voltage across the brushes.
• The commutator is made of copper segments insulated from each other by mica sheets and it's mounted on the shaft of the machine. 

5. Brushes:-

• The goal of brushes is to ensure electrical connection between the rotating commutator.
• The brushes are made of carbon and lie on the commutator. 
• The brush pressure is adjusted by means of adjustable springs.