User Manual

SENR9977 13
Systems Operation Section
The alternator is connected to the battery through
theignitionsw
itch. Therefore, alternator excitation
occurs when the switch is in the ON position.
Starting Motor
g00956095
Illustration 9
24 Volt Starting Motor
(1) Terminal for connection of the ignition
switch
(2) Terminal for c onnection of the battery
cable
g00954820
Illust
ration 10
12 Volt Starting M otor
(1) Terminal for connection of the battery cable
(2) Terminal for connection of the ignition switch
The sta
rting motor turns the engine flywheel. The
rpm is high enough in order to initiate a sustained
operation of the fuel ignition in the cylinders.
The starting motor has a solenoid. When the ignition
switch is activated, voltage from the electrical system
will cause the solenoid to engage the pinion in the
flywheel ring gear of the engine. When the pinion
gear is engaged in the flywheel ring gear, the
electrical contacts in the solenoid close the circuit
between the battery and the starting motor. This
causes the starting motor to rotate. This type of
activation is called a positive shift.
When the engine begins to run, the overrunning
clutch of the pinion drive prevents damage to the
armature. Damage to the armature is caused by
excessive speeds. The clutch prevents damage by
stopping the mechanical connection. However, the
pinion will stay meshed with the ring gear until the
ignition switch is released. A spring in the overrunning
clutch returns the clutch to the rest position.