Explain the principle and operation of d.c. crompton potentiometer

Explain The Principle And Operation Of D.C. Crompton Potentiometer Generator Is Not

Again depending upon the resources the turbine may be a water turbine, steam turbine, gas turbine, etc.

The two ends of the coil are connected to two slip rings, S 1, S 2 which are mounted on the same shaft.

The slip rings are insulated from each other from the shaft, these slip rings rotate along with the coil.

The stationary brushes b 1, b 2 be make proper contact with rotating slip rings and lead the current induced in the coil to the external load resistance R.

The value of induced e.m.f.

The conductor has a maximum e.m.f.

During this half revolution, The flow of current is along BAMLDCB.

R is from M to L.

In the next half revolution i.e.

CDLMABC and current through R is from L to M.

It also must be understood that the current not only reverse its direction but also changes its magnitude at every instant, and the current is known as alternating (ac) current.

The corresponding voltage is known as dynamically induced e.m.f.

For making the flow of current unidirectional in the external load circuit, the slip-rings are replaced by split-ring.

The split-rings are made of a conducting cylinder, which is cut into two halves or segments insulated from each other and the shaft with ( a thin mica sheet ) insulating material.

The two ends of the coil are connected to these segments ( s 1, s 2 ) and the brushes ( b 1, b 2 ) placed over these segments.

In the next half revolution, the direction of the induced current in the coil will be reversed.

But at the same time, the position of segments S 1 and S 2 have also reversed, with the result that brush b 2 comes in contact with segment S 2 which is now ve and the brush b 2 is in contact with segment S 1 which is now -ve.

Thus the current in the external load R again flows from M to L.

It should be noted that the current induced in the coil sides is alternating, but it becomes unidirectional in the external load due to the rectifying action of the split ring known as a commutator.

Explain The Principle And Operation Of D.C. Crompton Potentiometer Generator Is Not

A pulsating direct current such as given by a single coil generator is not suitable for most commercial purposes.

However by employing a large number of coils and commutator segments, with the coils evenly distributed around the surface of the armature the voltage can be increased and may be kept constant.

Usually, the negative half-wave of AC generated in armature winding is converted to positive half by the commutator ( or split-ring ).

The alternating current induced in armature conductors is made unidirectional in the external load due to rectifying or conversion action of split-ring or commutator.

The prime mover may be a diesel petrol engine, or a turbine depending upon the rating and application of the generator.

The prime mover converts some sort of energy ( diesel petrol water steam gas etc ) into mechanical energy.

Thus mechanical energy is supplied to the generator ( i.e., generator input ).

If the generator is very big like in power stations then the prime mover will be a turbine.