Manitowoc Grove GRT8120, Operator'S Manual

Page: 177 / 448

Grove
Published 3-22-2021, Control # 702-02
4-47
GRT8120 OPERATOR MANUAL OPERATING PROCEDURES
4
Figure 4-50 shows the expected typical boom configurations
for the three criteria that have been entered. Note that the
first row has the radius and load highlighted in green. These
green values indicate the maximum values in the table; the
172.8 ft boom length pinning combination has the highest
possible radius and load. For the column with the
approximate time to extend the boom, the green highlighted
value in the fourth row is actually the minimum value (since a
shorter time is expected to be the most desirable). Also, note
that the orange color for highlighting/selecting a row can
“hide” the green color, but the italics is also used to try to
distinguish these items. Use the up and down arrow icons at
the right side of the screen to change the highlighted row and
then see all the green colored items.
Once a selection is made, the OK button can be used (if the
telescoping function has been activated) to proceed to use
the boom configuration in the Semi-auto mode. Another
option is to change the rigging information as explained next.
The rigging information on the Rated Capacity Display
Module (RDM) can be changed as follows:
• Outriggers at 50% extension.
• Use the check-mark to activate new rigging.
If the Boom Configurator screen is still shown, the table of
values should update.
Finally, if it is desired to keep lifts within a criterion such as
75% of the maximum values for the load chart data, then the
search can be based on a modified hook load. The modified
hook load value would be the hook load divided by the
decimal value for the desired limitation such as the following:
P
modified
= P / 0.75
For example, if hook load is 10,000 lbs, and 0.75 is the
modification desired, then the value to enter on the Boom
Configurator screen would be the following:
P
modified
= 10,000 / 0.75
P
modified
= 13,333
Thus, enter the value of 13.5 klbs for the Boom Configurator.
Lowering and Raising the Main Hoist Rope
NOTE: When load is stopped at desired height, the
automatic brake will engage and hold the load as
long as the controller remains in neutral.
Lowering the Main Hoist Rope
Dual Axis Controllers
1. Push the Main Hoist Enable/Disable Switch on right
armrest to enable the main hoist function.
The Main Hoist Enable Indicator in the Status Bar area
(Figure 4-73) of the ODM will come on (green).
2. Push controller on right armrest forward and hold to
lower the main hoist rope.
3. When hook block/overhaul ball gets to the desired
height, let controller return to the center (neutral)
position to stop lowering the main hoist rope.
NOTE: When the main hoist controller is pushed forward to
lower the rope, the Hoist Rotation Indicator (27,
Figure 3-9) pulses and the Main Hoist Lower
Indicator (Figure 4-73) comes on to indicate to the
operator that the main hoist is operating.
Single Axis Controller (Optional)
1. Push the Main Hoist Enable/Disable Switch on right
armrest to enable the main hoist function.
The Main Hoist Enable Indicator in the Status Bar area
(Figure 4-73) of the ODM will come on (green).
2. Push outer controller on right armrest forward and hold
to lower the main hoist rope.
3. When hook block/overhaul ball gets to the desired
height, let controller return to the center (neutral)
position to stop lowering the main hoist rope.
NOTE: When the main hoist controller is pushed forward to
lower the rope, the Hoist Rotation Indicator
10254-22
FIGURE 4-50
Example Only
DANGER
Crushing Hazard!
Keep area beneath load clear of all obstructions and
personnel when lowering or raising rope (load).
DANGER
Crushing Hazard!
Do not jerk controller when starting or stopping hoist.
Jerking controller causes load to bounce, which could
result in possible damage to the crane.