Service Manual Instruction Manual

SECTION 3 - CHASSIS & TURNTABLE
3121171 – JLG Lift – 3-191
3.30 AUXILIARY POWER SYSTEM
The Auxiliary Power System is intended as a secondary means
of moving the boom in the event of primary power loss. This
system uses an electric motor/pump unit powered by a 12V
battery capable of operating all functions except drive and
controlled boom angle (see Section 4.11, Controlled Boom
Angle System). To reduce the demand on the battery and
therefore extend the run time of the system, the auxiliary
power functionality differs from the primary power functional-
ity. When commanded, the control system will attempt to use
the force of gravity to operate main lift down, tower lift down,
and tower telescope in by supplying pilot pressure to the
respective cylinders. If appropriate movement is not detected
by the boom sensors, the auxiliary power system will supply
the hydraulic flow to power the movement conventionally.
The envelope control system (see Section 4.6, Envelope Con-
trol System) remains active during the auxiliary power opera-
tion, however, the functionality of tower lift or main lift only
approximates the normal tower path control (see Section 4.7,
Tower Path Control System) or main boom control (see Section
4.8, Automatic Main Boom Control System) functionality.
Rather than the normal combined movements of tower lift,
tower telescope, and main lift, these movements will automat-
ically alternate during commands for tower lift or main lift to
approximate the movements made under normal engine
power.
3.31 COUNTERWEIGHT
If the counterweight has been removed, ensure the retaining
bolts are torqued to the proper value as shown in Figure 3-79.,
Counterweight Bolt Torque.