JLG 18RS Service Manual - Manual (Page 78)

SECTION 3 - CHASSIS & TURNTABLE
3-40 – JLG Lift – 3121284
Mid Engine RPM
Mid Engine RPM occurs when all of the following conditions
exist;
1. The Engine State is Engine Running.
2. The operator is not shutting down the engine.
3. The control system is not commanding a higher engine
RPM (Multi-function or High Engine).
4. The control system is not calling for Generator RPM.
5. Platform mode is active with the controls enabled or
Ground mode is active with any function enabled
except for Lift Down, Tower Lift Down, or Jib Lift Down.
High Engine RPM
High Engine RPM occurs when all of the following conditions
exist;
1. The Engine State is Engine Running.
2. The operator is not shutting down the engine.
3. The control system is not calling for Generator RPM.
4. The operator is operating the Drive function at Max
Torque or Max Speed.
5. Drive Forward or Drive Reverse is being operated.
Generator RPM
Generator RPM occurs when all of the following conditions
exist;
1. The Engine State is Engine Running.
2. The operator is not shutting down the engine.
3. The Control System is configured for a generator.
4. The Platform Generator Switch is Enabled and Selected.
3.14 ENGINE CONTROLS
Alternator Excitation
For the alternator to charge, it must be rotating and the alter-
nator excitation terminal must be energized by an external
power source. This power is supplied by the Ground Module
through terminal J1-32 to the D+ terminal on the alternator.
This terminal includes a one-way blocking diode that prevents
reverse energy flow into the Ground Module during engine
power-down. This terminal is continuously energized after
startup.
VBatt
J1-32 put Out
Alternator
Ground Module
D+
Figure 3-13. Alternator Schematic