Generator Field

Generator output is controlled by PCM based on battery voltage and temperature input. PCM keeps charging system output voltage at 12.9-15.0 volts. Charging system output voltage is controlled by generator voltage regulator (field control), located within PCM. Voltage determined by PCM as final goal for charging system is called "control" voltage. Control voltage will be used to determine generator field control and to detect if charging system is operating properly.

If sensed voltage is lower than control voltage, PCM will alter duty cycle and ground generator (rotor) field for a longer period of time and create a higher generator output which should raise sensed voltage level. If sensed voltage is higher than control voltage, PCM will alter duty cycle and lower generator output, which should lower sensed voltage level.