Manitowoc National Crane 600E-2 User Manual

National Crane PUBLISHED 04-26-2019 CONTROL # 113-09 3-9
600E2 OPERATOR MANUAL OPERATING CONTROLS AND PROCEDURES
3
HCA SYSTEM OPERATION
Once an over-capacity conditions reached, the HCA will not
allow the operator to move the load to a greater radius.
Pressure Sensing Switch
When trip pressure is reached, the pressure sensing switch
breaks electrical continuity to the work port unloader
solenoid in the main control valve. When power is removed
from this solenoid, the unloader valves allow the oil flowing to
hoist up, telescope out and boom down to flow to tank. This
path to tank will prevent further operation of these functions.
When the overload condition is corrected by hoisting down,
retracting the boom, or raising the boom, the pressure
sensing switch allows the work port unloader solenoids to be
powered thereby allowing the crane to function normally.
During the operation at near capacity loads, care must be
taken to operate the controls smoothly or the system may be
shocked into the dump mode prematurely.
Caution should be exercised when operating near 80° of
boom elevation. If the boom lift cylinder is fully extended and
pressurized above trip pressure, the system solenoid will
deactivate and the boom will remain locked at 80°. To correct
this condition, momentarily actuate the override switch and
boom down approximately 5°. Some units may be equipped
with a Manual Reset Valve Option that can be used to unlock
the unit from 80°.
The override system consists of a key switch and a
momentary push button switch.The key switch provides
power to the momentary push button switch located on the
console.To momentarily override, activate key switch and
depress push button on console. This will activate the work
port unloader solenoid and return power to hoist up,
telescope out, and boom down functions.The override switch
is not to be used during normal use of the crane or as an aid
in using the crane in an overload or anti-two blocked
condition.
The load range gauge is provided to aid the operator when
operating near the rated capacity of the crane. The gauge
only provides accurate indication when the lift control lever is
in neutral. The gauge movement is not proportional to the
load on the hook. It is not unusual for the indicator to be in
the red area at less than rated load condition when operating
the lift control, especially during boom down operation.
EXTENSION LOAD LIMITING DEVICE
System Description
The extension load limiting device is an electro-mechanically
operated, maximum capacity sensing device that stops all
normal crane functions that cause overload when maximum
capacity of the extension is exceeded. In the event that an
over capacity condition occurs, the extension load limiting
device is actuated by sensing excessive force on a load cell
which causes the boom down, extend out, and hoist up
functions to become inoperative. These are the functions
that increase the over capacity condition. On extensions with
a manually extendable section, a configuration switch
operated by the extension retaining pin distinguishes
between an extended extension and a retracted extension.
This system allows for continued operation of the hoist down,
boom up, and boom retract functions, the functions that
normally allow the operator to bring the load to a shorter
operating radius or set the load down in order to eliminate an
over capacity condition. Once the excessive force on the
load cell has been reduced by bringing the load to a shorter
radius or setting the load down, normal operation can be
resumed. This system uses the work port unloader solenoid
in the anti-two-block system as the hydraulic system dump
circuit.
The extension load limiting system has an override switch
and button located on the operator’s console that
momentarily overrides the hydraulic capacity alert, the
extension load limiting device, and the anti-two-block system
and restores power to crane functions. Two indicator lights
located on the operator’s console alert the operator of
function power loss and discriminate between the hydraulic
capacity alert and the anti-two-block or extension load
limiting systems as the cause of power loss. In the event of a
two-block or extension overload condition, an audible alarm
will sound in addition to the lighting of the indicator light.
Do not use the override to continue lifting operations in an
overload or two blocked condition.
System Operation
The extension load limiting device will operate as stated in
the System Description Section. Once an over-capacity
condition is reached, the system will not allow the operator to
move the load to a greater radius. The truck may have to be
repositioned closer to the load in order to set the load at the
desired location.
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Reference
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Manitowoc National Crane 600E-2 Specifications

General

Brand	Manitowoc
Model	National Crane 600E-2
Category	Construction Equipment
Language	English