DC generator : Why DC compound generator is suitable for use lighting circuit?
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| DC compound Generator use in lightning circuit [figure 1] |
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| DC compound Generator use in lightning circuit [figure 2] |
Introduction
For lighting circuit required constant voltage and rated current. DC shunt generator and DC series generator cannot fulfilled the condition of voltage and current required in lighting circuit.
In DC shunt generator load current increase with decrease the terminal voltage and DC series generator load current is associated by rising in the terminal voltage But cumulative-compound generator is useful for lighting load with constant voltage and rated current.
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| DC compound Generator use in lightning circuit [figure 3] |
DC Compound Generator
The DC compound generator is a part of the third DC motor. With this in mind, this motor can work at the same time as a DC Shunt generator, just like a DC series motor.
This motor can be used in two ways. As a cumulative compound, which is a series field will help Shunt field excitation. Another way is differentially compounded, which is that a series field will controvert the shunt field Excitation.
It can also be used in three ways by changing the trans field of the DC Compound generator series field.Or it can be said that by changing the trans of series field different types of outputs are available with respect to type of Dc Compound generator. they can be used for different purposes like battery charging, lighting etc.
If we need high voltage & high current as a output then adjust the series field turns it is called over compound DC Generator. More briefly If turns Increase Resistance will decrease here we need two Equation for understand
Ise = (v-Ish Rsh )/Rse. ------------(1)
Here v is terminal voltage and series field current is equal to output current .
Here If Resistance of series field is decreased then current is also Increased.
And then
v=Eg -Ia Ra -Ise Rse,----------(2)
here Ia Ra is constant and also Eg is constant so If Rse decrease Increase the Ise and that result effect on Ise Rse so, v also Increase in nature.
We the output requirment load current Increase but voltage is constant then chenging the series field truns this method is called flat compounding. It is required for lightning and battery charging.
When we need very low voltage and high current less than a flat compound Dc generator then the series field trans will be reduced to less than a flat compound DC generator Then it is called Under Compound DC Generator.
Types of Dc Compound Generator
Mainly Dc Compound Generator is Two types
- Short Shunt Compound Generator
- Long Shunt Compound Generator
When shunt field parallel with series field and armature , series field connected with armature as series connection this Generator called Long shunt Compound Generator. As same like figure
Advantages of DC Compound Generator
Main advantage is the compound Generator can use for multiple output. It can also use as a Shunt Generator and it can aslo as a series Generator. When compound Generator use as a Motor then we get multiple output torque it can adjust as high Starting Torque motor or it can also use as a constant Torque motor.
Basically Dc Compound Generator With flat Compounded mode it is use for lightning and charging in traction system or industrial use..
Why compound Generator use lightning circuit?
Since the traditional lighting system is generated from an AC generator, the AC power was converted to DC through a converter. But nowadays DC compound generators are commonly used as dynamos in some traction systems because the amount of loss in AC is high.
It goes without saying that there is absolutely no loss in DC. And power loss in any traction system is not a job. The DC compound generator lighting system is used in the sense that the flat compound mode of the compound generator is capable of delivering constant voltage and high current as a battery does.
That’s why flat compound DC generator lighting systems are so popular. Same popular is traction backup charging system. Which means Dc flat compound Generator is suitable for battery charging
Theory
so let discuss how condition is fulfilled briefly.
In cumulative - compound generator with short shunt arrangement shunt field is directly connected to armature and load current flows through the series field.
So, Ise=IL. On other hand with long shunt arrangement armature and series field connected with series .so, Ia =Ise. In both case current in series field winding produced flux with related with shunt field winding.
When generator is connected to load naturally fall in terminal voltage due to load resistance drop and load current is suddenly increase.
Now change the series field amp- turns comparatively small. Which will have an effect on net flux and generated emf. It helps to terminal voltage remain constant as per load requirement.
Conclusion
In DC compound Generator is suitable for battery charging because the Generator output is controllable value and has steady state level .
Since compound Generator is provided control output so therefore it is also used in lightning circuits. Application of DC compound Generator is Hybrid cars and Constant output application is lightning circuit , battery charging , traction lighting circuit. Generally DC compound Generator use type for battery charging of lightning circuit is flat compound Generator .
Flat compound Generator provides constant voltage with current.Dc compound Generator has multiple applications in the industrial sector. Nowadays DC compound Generator is used in the traction sector for backup power supply.
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