Starting and Charging: Description and Operation

STARTER SYSTEM
When the ignition switch is moved to the START position, battery voltage is applied to the starter solenoid. Both solenoid windings are energized. The circuit through the Pull-In Winding is completed to ground through the starter motor. The windings work together magnetically to pull in and hold in the plunger. The plunger moves the shift lever. This action causes the drive assembly to rotate as it engages the flywheel ring gear on the engine. At the same time, the plunger also closes the solenoid switch contacts in the starter solenoid. Full battery voltage is applied directly to the starter motor and it cranks the engine.

As soon as the solenoid switch contacts close, voltage is no longer applied through the Pull-In winding since battery voltage is applied to both ends of the windings. The Hold-In winding remains energized and its magnetic field is strong enough to hold the plunger, shift lever and drive assembly solenoid switch contacts in place to continue cranking the engine.

When the ignition switch is released from the START position, battery voltage is removed from the PPL wire and the junction of the two windings. Voltage is supplied from the motor contacts through both windings to ground at the end of the Hold-In Winding. However, the voltage applied to the Pull-In Winding is now opposing the voltage applied when the winding was first energized. The magnetic fields of the Pull-In and Hold-In Windings, with the help of the Return Spring, cause the drive assembly to disengage and the solenoid switch contacts to open simultaneously. As soon as the contacts open, the starter circuit is turned off.


CHARGING SYSTEM
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.

The Generator's regulator uses digital techniques to supply the rotor current and thereby control the output voltage. The rotor current is proportional to the width of the electrical pulses supplied by the regulator. When the ignition switch is placed in RUN, voltage is supplied to the BRN wire which turns on the Regulator. Narrow width pulses which are supplied to the rotor, create a weak magnetic field. 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 varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation.