Generator
The generator features the following major components:
• | The rotor with slip rings and brushes |
The pulley and the fan cool the slip ring and the frame.
The generator features permanently lubricated bearings. Service should only
include tightening of mount components. Otherwise, replace the generator as a
complete unit.
Regulator
The voltage regulator controls the rotor field current in order to limit the
system voltage. When the field current is on, the regulator switches the current
on and off at a rate of 400 cycles per second in order to perform the following
functions:
• | Obtain the correct average current needed for proper system voltage control |
At high speeds, the on-time may be 10 percent with the off-time at 90 percent.
At low speeds, the on-time may be 90 percent and the off-time 10 percent.
Circuit Description
The generator provides voltage to operate the vehicle's electrical system and
to charge its battery. A magnetic field is created when current flows through
the rotor. This field rotates as the rotor is driven by the engine, creating
an AC voltage in the stator windings. The AC voltage is converted to DC by
the rectifier bridge and is supplied to the electrical system at the battery
terminal.
When the ignition is in the RUN position battery voltage is supplied through
the Ignition 1 relay to the generator , turning on the regulator. The generator's
voltage regulator controls current to the rotor, thereby controlling the
output voltage. The rotor current is proportional to the electrical pulse
width supplied by the regulator. When the engine is started, the regulator
senses generator rotation by detecting AC voltage at the stator through an
internal wire. Once the engine is running, the regulator uses the voltage sense
circuit from the underhood fuse block to varie the field current by controlling
the pulse width. This regulates the generator output voltage for proper battery
charging and electrical system operation. .
Charge Indicator
The charge indicator is a LED located in the I/P cluster. It receives battery
voltage when the ignition is in the RUN position. The circuit is grounded through
the L terminal of the generator.
The generator will ground the L terminal when the regulator detects one of the
following conditions:
• | Sense voltage below 9.5 V |