1. No-Load Characteristics
The no-load characteristics of shunt generator is same as that of separately excited generator because small current in armature which is field current under no-load conditions does not impact much on the no-load characteristics.
Load characteristics is also same as separately excited DC generator but there is small difference as in shunt generator because for a shunt generator
Ia = IL + If
In separately excited generator
Ia = IL
CD = IaRa drop
DF = armature reaction drop
FG = Drop due to fall If
Terminal voltage falls due to CD and DF due to which If decreases which leads to further decrease in Va
As load is increased (IL increased), Vt decreases till 'B' and if IL is further increased, Ia increases so more armature reaction is produced which reduces Vt and If. The reading in Vt is so large that IL decreases.
OH = current due to residual flux voltage
IFL = full load current
IM = maximum current
4. Armature Characteristics
We can obtained armature characteristics by running shunt generator as separately excited generator.
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