DC Generators
DC GENERATOR CONSTRUCTION
Rev. 0
Page 15
ES-05
Figure 10 Series-Wound DC Generator
Figure 11 Output Voltage-vs-Load Current for Series-Wound
DC Generator
Series-Wound
DC Generators
When the field winding of a DC
generator is connected in series
with the armature, the generator
is
called
a
series-wound
generator (Figure 10).
The excitation current in a
series-wound generator is the
same as the current the
generator delivers to the load.
If the load has a high resistance
and only draws a small amount
of current, the excitation
current is also small. Therefore,
the magnetic field of the series
field winding is weak, making
the generated voltage low.
Conversely, if the load draws a large current, the excitation current is also high. Therefore,
the magnetic field of the series field winding is very strong, and the generated voltage is high.
As you can see in Figure 11, in a
series generator, changes in load
current drastically affect the
generator output voltage. A
series generator has poor voltage
regulation, and, as a result, series
generators are not used for
fluctuating loads. As is the case
for the shunt-wound generator, a
series-wound
generator
also
exhibits some losses due to the
resistance of the windings and
armature reaction. These losses
cause a lower terminal voltage
than
that
for
an
ideal
magnetization curve.
