Series Generators

When the field winding is connected in series with the armature winding while supplying the load then the generator is called series generator. It is shown in the Fig. 1.

Field winding, in this case is denoted as S₁ and S₂. The resistance of series field winding is very small and hence naturally it has less number of turns of thick cross-section wire as shown in the Fig. 1.

Let R_se be the resistance of the series field winding.

1.1 Voltage and current Relations

As all armature, field and load are in series they carry the same current.

.^..         I_a = I_se =  I_L

Where   I_se = Current through series field winding.

Now in addition to drop I_a R_a, induced e.m.f. has to supply voltage drop across series field winding too. This isI_se R_se i.e. I_a R_se as I_a = I_se. So voltage equations can be written as,

E = V_t + I_a R_a + I_a R_se + V_brush
.^..      E = V_t + I_a (R_a + R_se) + Vbrush
where  E = (?PNZ)/(60A)