In this post, you will learn the characteristics of a series wound dc generator. This article is the continuation of the dc generator characteristics.
The connection diagram of a series-wound generator is shown in the figure below.
![dc series generator connection](https://studyelectrical.com/wp-content/uploads/2014/08/dc-series-generator-connection.png)
The open circuit, internal and external characteristics of series wound dc generators are discussed here.
Open circuit characteristic
Curve 1 shows the open circuit characteristic (O.C.C.) of a series generator. Curve 2 shows the total or internal characteristics of a series generator. Curve 3 shows the external characteristic of a series generator.
![Dc series generator characteristics](https://studyelectrical.com/wp-content/uploads/2014/08/dc-series-generator-characteristics.png)
Internal characteristic
Curve 2 shows the total or internal characteristics of a series generator. It gives the relation between the generated e.m.f. E. on load and armature current.
![internal characteristics](https://studyelectrical.com/wp-content/uploads/2014/08/internal-characteristics.png)
Due to the armature reaction in the dc generator, the flux in the machine will be less than the flux at no load.
Hence, e.m.f. E generated under load conditions will be less than the e.m.f. E0 generated under no-load conditions.
Consequently, the internal characteristic curve lies below the OCC curve; the difference between them representing the effect of armature reaction.
External or Load characteristic
Curve 3 shows the external characteristic of a series generator.
It gives the relation between terminal voltage and load current IL.
Therefore, external characteristic curve will lie below internal characteristic curve by an amount equal to ohmic drop [i.e., Ia(Ra + Rse)] in the machine.
Note:
If it is operated on the drooping portion of the characteristic, it gives approximately constant current irrespective of the external load circuit resistance.
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