Manitowoc 999 Service And Maintenance Manual

Reference Only
Manitowoc Published 05-16-17, Control # 233-03 1-43
999 SERVICE/MAINTENANCE MANUAL INTRODUCTION
1
Gantry System
See Figures 1-32 and 1-33
The PC controls the gantry and mast raising sequence.
When in crane setup mode and the mast angle is less than
25°, the PC sends an output signal to boom hoist brake
release solenoid HS-13 and boom hoist drum pawl out
solenoid HS-15. This permits boom hoist drum to haul in or
pay out wire rope to reeving between gantry and mast
sheaves as the gantry is raised or lowered.
When raising gantry, boom hoist system hydraulic pressure
is monitored by the PC with boom hoist pressure sender (12)
and controlled by the PC to maintain a minimum rope tension
on the boom hoist drum.
The gantry switch (2) on remote setup control should only be
used for raising/lowering gantry without wire rope or
installing/removing counter weights with mast laying forward.
Power is available to setup remote control when cable is
plugged into valve junction box on left side of rotating frame
and engine is running. Pressing power button (3) completes
power supply circuit to setup remote control switches.
A gantry operating limit message GANTRY DOWN appears
on the digital display screen when gantry and the mast angle
is 22° or more. The PC detects this fault when the mast angle
sensor (4) monitors the mast position at 22° and gantry up
limit switch (5) circuit to the PC is closed. The operator
should raise gantry with the gantry switch in raise position.
Each gantry cylinder (6) has a counterbalance valve (7) at
each cylinder port. These valves ensure smooth control
when raising or lowering gantry and locks the cylinder in
place when gantry is at a desired position or if a hydraulic
line fails.
Gantry accessory valve is "motor spool" where both cylinder
ports and tank port of valve spool section are connected in
center position. This type of spool prevents premature
opening of load equalizing valves (8).
Gantry Cylinders Raise
See Figures 1-32 and 1-33
Place boom hoist brake switch (9) in off - park position. Boom
hoist brake remains spring-applied to boom hoist drum until
the PC releases the brake. Boom hoist drum pawl out
solenoid HS-15 is enabled to disengage pawl from boom
hoist drum. Boom control handle circuit to the PC remains
open.
NOTE: Always confirm hydraulic and electrical schematics
by serial number of crane.

Manitowoc 999 Specifications

General

Brand	Manitowoc
Model	999
Category	Construction Equipment
Language	English