Komatsu 730E Operation & Maintenance Manual page 85

OM3223
Operator Cab and Controls
Hoist Control Lever
Hoist control (4, Figure 32-7) is a four position hand-
operated lever located between the operator seat
and the center console.
To Raise Dump Body
1. Pull the lever to the rear to actuate the hoist cir-
cuit. (Releasing the lever anytime while raisin
gthe body will place the body in HOLD at that
position.)
2. Raise the engine rpm to increase hoist speed.
3. Reduce engine rpm as the last stage of the
hoist cylinders begin to extend and then let the
engine go to low idle as the last stage reaches
half-extension.
4. Release the hoist lever as the last stage
reaches full extension.
5. After the material being dumped clears the
body, lower the body to frame.
Refer to operating instructions, dumping for more
complete details concerning this control.
FIGURE 32-8. HOIST CONTROL LEVER
To Lower Dump Body
Move the hoist lever forward to the DOWN position
and release. Releasing the lever places the hoist
control valve in the FLOAT position allowing the body
to return to the frame.
Retard Speed Control (RSC) Adjust Dial
RSC adjust dial (5, Figure 32-7) allows the operator
to vary the downhill truck speed that the retard speed
control system will maintain when descending a
grade.
When the dial is rotated counterclockwise
toward this symbol, the truck will descend
a grade at lower speeds.
When the dial is rotated clockwise toward
this symbol, the truck speed will increase.
Throttle pedal position will override the RSC setting.
If the operator depresses the throttle pedal to
increase truck speed, dynamic retarding will not
come on unless truck overspeed setting is reached
or the foot operated retard pedal is used. When the
throttle pedal is released and the RSC switch is ON,
dynamic retarding will come on at, or above, the RSC
dialed speed and will adjust truck speed to, and
maintain, the dialed speed.
To adjust the RSC control, pull switch (6) on and start
with dial (5) rotated toward fastest speed while driv-
ing the truck at the desired maximum speed. Relax
the throttle pedal to let the truck coast and turn RSC
adjusting dial slowly counterclockwise until dynamic
retarding is activated. Dynamic retarding will now be
activated automatically anytime the set speed is
reached, the RSC switch is ON, and throttle pedal is
released.
With the RSC switch ON and dial adjusted, the sys-
tem will function as follows: As truck speed increases
to the set speed and the throttle pedal released,
dynamic retarding will apply. As truck speed tries to
increase, the amount of retarding effort will automati-
cally adjust to keep the selected speed. When truck
speed decreases, the retarding effort is reduced to
maintain the selected speed. If truck speed continues
to decrease to approximately 4.8 kph (3 mph) below
set speed, dynamic retarding will turn off automati-
cally. If truck speed must be reduced further, the
operator can turn the adjust dial to a new setting or
depress the foot operated retard pedal.
If the operator depresses the foot operated retard
pedal and the retard effort called for is greater than
that from the automatic system, the foot pedal retard
will override RSC.
Operation - Section 32
Page 32-7