Komatsu 830E-AC Shop Manual page 201

CRANKING MOTORS
Operation
Heavy duty batteries supply 24VDC to each of the
two cranking motors through magnetic switches acti-
vated by the key switch on the instrument panel.
Note: When a Komatsu SDA16V160 engine with a
prelube system is installed, there is a delay between
the time the key switch is moved to the START
position, and the cranking motors actuate.
When the key switch is placed in the Start position,
the magnetic switches close, connecting the motor
solenoid "S" terminals to the batteries. When the
solenoid windings are energized, the plunger (56,
Figure 2-6) is pulled in, moving the cranking motor
drive (71) assembly forward in the nose housing to
engage the engine flywheel ring gear. Also, when the
solenoid plunger is pulled in, the main solenoid con-
tacts close to provide current to the motor armature
and cranking takes place. When the engine starts, an
overrunning clutch in the drive assembly protects the
armature from excessive speed until the key switch is
released. When the key switch is released, a return
spring causes the drive pinion to disengage.
After the engine is running, a normally closed pres-
sure switch senses engine oil pressure and opens
the electrical circuit to prevent actuation of the
motor(s) after the engine has started.
Removal
1. Disconnect battery power:
a. Open the battery disconnect switch to
remove power from the system.
b. Disconnect the negative (-) battery cables
first.
c. Disconnect the battery positive (+) battery
cables last.
2. Mark wires and cables and remove from crank-
ing motor (2, Figure 2-4) and solenoid (3) termi-
nals.
3. Remove cranking motor mounting cap screws
(1).
4. Remove cranking motor assembly from fly-
wheel housing.
D02034
24 VDC ELECTRIC START SYSTEM
24 VDC Electric Supply System
FIGURE 2-4. CRANKING MOTORS
1. Cap Screws
2. Cranking Motor
Installation
1. Align cranking motor (2, Figure 2-6) housing
with the flywheel housing adaptor mounting
holes and slide into position.
2. Insert cranking motor cap screws (1).
3. Connect marked wires and cables to cranking
motor and solenoid terminals.
4. Install in the following sequence:
a. Connect the battery positive (+) cables first.
b. Connect the battery negative (-) cables.
5. Close the battery disconnect switch.
3. Solenoid
D2-11