Manitowoc 18000 Service Maintenance Manual

Reference Only
Manitowoc Published 12-05-17, Control # 035-23 1-49
18000 SERIVCE/MAINTENANCE MANUAL INTRODUCTION
1
When drum control handle is moved to neutral position,
node-1 controller compensates for hydraulic system leakage
or changing engine speed. Node-3 controller sends a zero
output voltage to pump EDC that moves swashplate to
center position. This shifts the motor back to maximum
displacement for slower output speed to slow the drum
rotation. Node-1 controller stores the load holding pressure
in pressure memory. After control handle center switch
opens, node-3 controller sends a zero output voltage to
disable drum brake solenoid valve HS-8 to apply brake
before load drum pump de-strokes.
The diverting valve lines to whip line hoist motor remain open
until main hoist 1 control handle is selected for operating
main hoist 1.
Whip Line Hoist Lowering
The following load drum lowering operation is for whip line
hoist while operating in Standard mode.
When whip line hoist control handle is moved forward for
lowering load, an input voltage of 2.4 volts or lower is sent to
node-1 controller. Node-4 controller sends a 24 volt output to
drum 3 diverting solenoid valve HS-9 to shift valve and open
lines to drum 3 motor and close lines to main hoist 1 left side
drum motor. Node-3 controller sends a variable zero to 24
volt output that is divided by a resistor and applied to main
hoist pump 1/3 EDC in the hoist direction. Node-3 controller
sends a variable zero to 24 volt output that is divided by a
resistor and applied to whip line motor PCP. Node-1
controller checks that drum block-up limit switches are
closed and no hydraulic system faults are present.
Main hoist 1/3 pump EDC tilts swashplate in the up direction
to satisfy pressure memory. Node-1 controller compares
drum holding pressure to value in pressure memory. When
system pressure is high enough, node-3 controller sends a
24 volt output to enable drum brake solenoid valve HS-8.
The drum brake solenoid shifts to block drain port and opens
port to low-pressure side of drum system to release brake.
When brake is released, node-3 controller sends a 24 volt
output voltage to pump EDC to tilt swashplate to stroke
pump in the lower direction. In the lower direction, hydraulic
fluid flow is from port B of pump to port A of motor. Return
fluid is from port B of motor to port A of pump.
Controller output voltage to pump EDC and motor PCP is
relative to control handle movement. As drum control handle
is pushed forward, an output voltage increases the pump
swashplate angle. When system pressure exceeds the
PCOR valve setting of 4,930 psi (340 bar), the valve shifts to
direct flow from shuttle valve into maximum displacement
side of servo cylinder. The PCOR valve over-rides the
command from servo PC valve, increasing motor
displacement and output torque and reducing output speed.
When PCOR valve closes, control of the motor returns to
servo PC valve.
Node controllers are continuously balancing the system
pressure and the motor displacement angle so the motor
displacement goes to minimum when control handle is all the
way forward, if the motor torque requirement is not too high.
Node-3 controller monitors motor displacement and controls
motor speed by regulating the hydraulic fluid flow through the
pump.
The load weight attempts to drive motor faster than return
fluid can return to low-pressure side of pump. System pump
maintains fluid supply at a positive pressure to motor. Pump
swashplate position restricts motor over speed. Pressure
builds on fluid return side of closed-loop, acting as a
hydraulic brake to control lowering speed.
When drum control handle is moved to neutral position,
node-1 controller compensates for hydraulic system leakage
or changing engine speed. Node-3 controller sends a zero
output voltage to pump EDC that moves swashplate to
center position. This shifts the motor back to maximum
displacement for slower output speed to slow the drum
rotation. Node-1 controller stores the load holding pressure
in pressure memory. After control handle center switch
opens, node-3 controller sends a zero output voltage is sent
to disable drum brake solenoid valve HS-8 and to apply
brake before pump de-strokes.
The diverting valve lines to whip line hoist motor remain open
until main hoist 1 control handle is selected for operating
main hoist 1.

Manitowoc 18000 Specifications

General

Brand	Manitowoc
Model	18000
Category	Construction Equipment
Language	English