Manitowoc 999 Service And Maintenance Manual

Reference Only
INTRODUCTION 999 SERVICE/MAINTENANCE MANUAL
1-30
Published 05-16-17, Control # 233-03
solenoid HS-16 to spring-apply brake before front drum
pump de-strokes.
Luffing Jib Operation (Optional)
See Figures 1-17, 1-18, 1-19, and 1-20
Luffing jib hoist is operated with rear drum handle (2) with
front drum as the main load line. Rear drum load handling
operation in luffing mode is identical to front drum while
performing crane operations in full power mode.
When rear drum brake switch is placed in on - park, auxiliary
drum pawl in solenoid HS-24 is enabled and pawl is
engaged. Drum brake release solenoid HS-21 is spring-
applied to auxiliary drum. When rear drum brake switch is
placed in off - park position, drum pawl out solenoid HS-25 is
enabled and pawl is disengaged. Rear drum brake remains
spring-applied to drum and is controlled automatically by the
PC with movement of control handle.
If a block up limit or LMI operating fault occurs while luffing,
the PC sends a command to stop the rear drum. Corrective
action for these operating faults is to raise the jib. In full
power mode, corrective action requires lowering load with
the rear drum.
FIGURE 1-20
HS-20 or HS-25
.06
X
X
6 GPM
B
A
B
A
SERVO PRESSURE
CHARGE PUMP
LOW PRESSURE SIDE
HIGH PRESSURE SIDE
350 PSI
(24 BAR
)
HS-16
FRONT OR REAR
LOW PRESSURE
BRAKE
PAWL
SUPERCHARGE
MANIFOLD
CHARGE
PUMP
FROM TRAVEL
PILOT
FRONT OR REAR LOAD DRUM PUMP
999CSM1-119
3
5
3
6
3
6
3
3
REAR
DRUM
ONLY
REAR DRUM ONLY
TO UPPER
ACCESSORY VALVE
or
HS-21
3
7
LOAD DRUM
3
4
HS-19 or HS-24
REAR DRUM TO
ACCESSORIES
LOW PRESSURE

Manitowoc 999 Specifications

General

Brand	Manitowoc
Model	999
Category	Construction Equipment
Language	English