TM 5-3810-307-24-1-2
As speed and output increase, voltage available at
OPERATING PRINCIPLES
the diode trio becomes sufficient to supply field
current for normal operation. When the output
A generator is a voltage-creating machine. The
voltage exceeds the battery voltage, the generator
voltage regulator limits the maximum voltage that
begins to drive the system voltage. If the wiring
the generator will produce at the output (BAT)
system includes an indicator light, the presence of
terminal by controlling the magnetic field present in
system voltage at the diode trio equalizes the
the rotor. The voltage produced allows current to
voltage on both sides of the indicator light and the
flow to satisfy the electrical loads placed on the
light goes out.
system, up to a maximum current characteristic of
the generator design.
While the system voltage is below the voltage
regulator setting, the regulator turns on the field
Schematics of the generator circuitry are shown in
current through the rotor and allows the generator
Figure 4 (one-wire systems)
to produce as much output as possible for the
generator speed (rpm), temperature and system
With the generator rotor turning, magnetic fields
voltage. When the voltage setting is reached, the
around the rotor induce voltages in the stator
regulator turns the field current off. When the field
windings. The faster the rotor turns, the higher the
current is turned off, the magnetic field in the rotor
induced voltage will be.
collapses and the generator output voltage begins
to fall. The falling voltage causes the regulator to
turn the field current back on and the magnetic
field to rebuild. This switching action of the
regulator continues rapidly, keeping the output and
system voltage very close to the voltage setting.
This will continue unless the electrical demands of
the system cause the system voltage to fall below
the voltage setting. Should this happen, the
regulator will again allow full field current to flow
so that the maximum output of the generator at the
given speed, temperature and system voltage is
realized.
One-wire systems use system voltage at the
generator to control the output voltage, and extra
sense wiring is not needed.
Figure 4. One-Wire Generator Schematic
