Figure 1-17.Compound-wound generator. In the compound-wound
generator when load current increases, the armature voltage
decreases just as in the shunt-wound generator. This causes the
voltage applied to the shunt-field winding to decrease, which
results in a decrease in the magnetic field. This same increase
in load current, since it flows through the series winding,
causes an increase in the magnetic field produced by that
winding. By proportioning the two fields so that the decrease in
the shunt field is just compensated by the increase in the
series field, the output voltage remains constant. This is shown
in figure 1-18, which shows the voltage characteristics of the
series-, shunt-, and compound-wound generators. As you can see,
by proportioning the effects of the two fields (series and
shunt), a compound-wound generator provides a constant output
voltage under varying load conditions. Actual curves are seldom,
if ever, as perfect as Figure 1-18.Voltage output
characteristics of the series-, shunt-, and