Crane Operation; Operating System; Hydraulic Components; Hydraulic Tank - Manitowoc 999 Service And Maintenance Manual

INTRODUCTION

CRANE OPERATION

999CSM1-100
Control
Handle
Handle
Command
Signal
Electronic
Displacement
Control (EDC)
Charge
Pump
Suction
Manifold

Operating System

See Figure 1-1
The Model 999 operating system is an EPIC
P r o c e s s e d I n d e p e n d e n t C o n t r o l ) . W i t h t h i s P C
(Programmable Controller) the independently powered
pumps and motors are controlled through operator
commands and control handles. The PC compares control
handle commands with monitored information from system
sensors. Crane information is displayed on a digital display
screen in operator's cab.
A diesel engine provides power to drive system pumps
through a gearbox.
In a closed-loop hydraulic system, high-pressure hydraulic
fluid from the system pump drives a hydraulic motor.
Pressure develops within the closed-loop system while
resistance of the load on motor is overcome. When
movement begins, pump volume displacement maintains
motor speed. Low-pressure side hydraulic fluid from motor
returns directly to pump input. The crane closed loop
systems are swing, right travel, left travel, boom hoist, front
drum, rear drum, and auxiliary drum.
1-4
Programmable Controller
Control Signal
(Pump Stroke)
Pressure
Feedback
Hydraulic
Pump
Swashplate
Low Pressure Side
Position
Line Legend
High-pressure Hydraulic, Positive Electrical
Negative Electrical (Ground)
Low-pressure Hydraulic, Signal Electrical
Control or Pilot Pressure Hydraulic
Hydraulic Suction
Case Return Pressure Hydraulic
Not Active Line or Circuit
®
(Electrical
Published 05-16-17, Control # 233-03
Control Signal
(Motor Stroke)
High Pressure
Side
Hydraulic
Piping
NOTE: In this manual, a hydraulic system that is "open"
means fluid can flow in the circuit. In this manual,
each hydraulic solenoid valve is assigned an HS
(hydraulic solenoid) number. The HS numbers
identify actual hydraulic solenoid valves on the
crane for training proposes only.

Hydraulic Components

See Hydraulic Schematic drawing at end of Section 2.

Hydraulic Tank

Hydraulic tank has a fill cap, separate breather, suction filter,
diffuser filter, high and low level sight gauges, vacuum,
temperature, and level sensors.
The tank has two sections: a suction section and a return
section. The suction section 100-mesh (150 micron) strainer
has a 3 psi (0.2 bar) bypass that allows flow around it if it
becomes plugged. A diffuser filter inside tank return line
reduces turbulence created by fluid returning to tank.
Tank hydraulic filters remove contaminants from fluid.
NOTE: System filtration does not transform deteriorated
fluid into purified quality fluid. Factors affecting
service life of hydraulic fluid include high operating
999 SERVICE/MAINTENANCE MANUAL
Motor Speed
Feedback
Pressure
Control Pilot
(PCP)
Hydraulic
Drum
Motor
FIGURE 1-1