JLG 1100S Service Manual - Manual (Page 130)

SECTION 3 - CHASSIS & TURNTABLE
3-88 – JLG Lift – 3121256
3.22 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 pow-
ered by a 12V battery capable of operating all functions
except drive, controlled arc, controlled boom angle, and
envelope tracking. During lift up or down functions, no
other functions are permitted and during lift up functions,
automatic platform leveling is not active. 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 functionality. The auxiliary power lift
down function supplies pilot pressure to the lift cylinder
allowing gravity to lower the boom. The system redirects
discharge oil from the lift cylinder to retract the telescope
cylinder. When the boom is retracted to the transport
length, the telescope in valve is dropped out and lift down
is operated alone allowing the platform to reach the
ground. This not only greatly reduces the power required
for these functions but also lowers the boom within the
envelope regardless of starting position. Envelope control
and moment control remain active during the auxiliary
power function.
1. Auxiliary Pump
2. Power Relay
3. Battery
Figure 3-58. Auxiliary Pump Installation