What is the principal of d.c. generator

Here present the artical of knowledge about principal of d.c. generator. And working.

A dc generator is machine which converts mechanical energy into electrical energy.
It is driven by some source of mechanical power i.e. prime mover.
A dc generator operated on the principal of the production of dynamically induced emf i.e. whenever flux is cut by the conductor dynamically induced e.m.f. is produced in it according to the laws of electromagnetic induction.

The basic essential components of a dc generator are

1.Magnetic field (field magnets):

Which produces the magnetic flux in the machine

2. Conductors:

The magnetic field is stationary and the conductors move.

For production of dynamically induced e.m.f. three things are nessesary.

Magnetic field
Conductors and
Motion of conductors w.r.t. the magnetic field.

The dynamically induced e.m.f .Produced in the conductors will cause a flow of electric current circuit is closed.

Action of commutator:

The e.m.f. induced in the armature conductors of a dc generator is alternating in nature.
It is rectified i.e. converts ac into dc in the external load circuit by the split-rings also known as commutator.
To make the flow of current indirectional in the external load circuit.
The split ring are made up of a conducting material and splitted into halves seperated by insulating material like mica.

In the first half revolution as shown in fig.

Current flows along ABRLcd i.e. brush B1 in contact with sagment s1 acts as the +ve end of the supply and brush B2 in contact with segment s2 acts as the -ve end of the supply.

In the next half revolution shown in fig the direction of induced current in the coil is reversed, but at the Same time the position of segments s1 and s2 are also reversed with the result that brushes B1 and B2 again come in contact with +ve segment S2 and -ve segment s1 respectvely.

Thus the direction of current in the external load circuit remains the same (unidirectional). The waveform the current through the external load circuit is shown in fig.