2-17
+ !
Once an over-capacity condition is reached, the sys-
tem 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.
When trip pressure is reached, the pressure sens-
ing switch opens the circuit that contain the Anti-Two
Block Solenoid. When power is removed from this so-
lenoid, the oil flowing to winch up, telescope out and
boom down is allowed to flow to tank. This path to tank
will prevent further operation of these functions. When
the overload condition is corrected by winching down,
retracting the boom, or raising the boom, the pressure
sensing switch allows the solenoid to be powered
thereby allowing the crane to function normally.
With the HCAJ selector switch set to the “JIB” posi-
tion and the Boom angle less than 75°, electrical conti-
nuity is broken to a mercury switch in the Wireline Jib
Min. Angle Switch.
This allows the oil flowing to Winch
Up, Telescope Out, and Boom Down to flow to tank,
preventing further operations of these functions. When
the overload is removed by booming up, the mercury
switch is energized and oil is no longer dumped to tank.
During the operation at near capacity loads with both
the HCAS and HCAJ, 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 sys-
tem solenoid will deactivate and the boom will remain
locked at 80°.
To correct this condition, momentarily
actuate the override switch and boom down approxi-
mately 5°. Some units may be equipped with a Manual
Reset Valve Option that can be used to unlock the unit
from 80°. See Controls & Hydraulics Section for addi-
tional description of this system.
The override switch is a momentary two position
switch normally in the off mode. The momentary on po-
sition is used to override the anti-two-block and hydrau-
lic capacity alert systems when they are activated. In
the override position, the switch powers the anti-two-
block solenoid returning flow back to winch up, telescope
out, and boom down momentarily. &#%4$&
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The load range gauge is provided to aid the opera-
tor 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 un-
usual for the indicator to be in the red area at less than
rated load condition when operating the lift control, es-
pecially during boom down operation.
The dual hydraulic capacity alert selector switch located on
the operators console must be set to the proper position.
The switch selects between two separate compensating
pressure switches. One pressure switch is set for sensing
overload pressures when BOOM is selected. The other
pressure switch
is set for sensing when JIB is selected.
"
!
If this crane is equipped with two Hydraulic Capacity
Alert systems, one for main boom and one for jib, the
Hydraulic Capacity Alert selector switch must be in
“JIB” position when lifting loads with the Jib.
Lifting loads with the jib while the main boom Hydrau-
lic Capacity Alert system is active will result in
DEATH OR SERIOUS INJURY.
Reference Only
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