A long-shunt compound generator delivers a load current of 50 A at 500 V and has armature, series field and shunt field resistances of 0.05 Ω, 0.03 Ω and 250 Ω respectively. Calculate the generated voltage and the armature current. Allow 1 V per brush for contact drop.

Generator circuit is shown in figure

Long Shunt Compound DC Generator

Current through shunt field winding, I_sh= 500/250 = 2 A

Current through armature and series winding = 50 + 2 = 52 A

Voltage drop on series field winding = 52×0.03 = 1.56 V

Armature voltage drop, I_aR_a = 52×0.05 = 2.6 V

Drop at brushes = 2×1 = 2 V

Now Emf generated in armature, Eg = V + I_aR_a+ series drop + brush drop
= 500 + 2.6 + 1.56 + 2 = 506.16 V