Komatsu PC500LC-10R Shop Manual page 112

ENGINE CONTROL SYSTEM
FUNCTION OF ENGINE CONTROL SYSTEM
Mechanism and function of engine starting system
• When starting switch (6) is turned to ON position, engine controller (8) sends a command current to fuel
supply pump (16).
Accordingly, a fail-safe mechanism is provided, that is, the engine stops when the electrical system has
trouble.
• When starting switch (6) is turned to START position while lock lever (9) is in LOCK position, the starting
current is supplied to starting motor (15) and the engine starts.
If lock lever (9) is in FREE position, starting motor cut-off relay (11) operates to cut off the starting current to
starting motor (15) and the engine does not start, that is, a neutral safety mechanism.
• Upon receipt of the engine cut-off command from the external source, KOMTRAX terminal (19) sends the
signal to machine monitor (18).
Machine monitor (18) operates starting motor cut-off relay (12) to cut off the starting current to starting mo-
tor (15), thus the engine does not start.
Mechanism and function of engine speed control system
10-18
10 STRUCTURE AND FUNCTION
PC500LC-10R