Komatsu 930E-2, Shop Manual

Page: 40 / 739

6. Maintain a safe distance when following another
vehicle. Never approach another vehicle from the
rear, in the same lane, closer than 50 ft. (15 m).
When driving on a down grade, this distance
should not be less than 100 ft. (30 m).
7. Do not stop or park on a haul road unless unavoid-
able. If you must stop, move truck to a safe place,
apply parking brake, and shut down engine be-
fore leaving cab. Block wheels securely and notify
maintenance personnel for assistance.
8. Before starting up or down a grade, maintain a
speed that will insure safe driving and provide
effective retarding under all conditions (refer to
“DYNAMIC RETARDING OPERATION”). The
Grade/Speed Chart in the operator’s cab should
always be referenced to determine MAXIMUM
safe truck speeds for descending various grades
with a loaded truck.
9. When operating truck in darkness, or when visi-
bility is poor, do not move truck unless all head-
lights, clearance lights, and tail lights are on. Do
not back truck if back-up horn or lights are inop-
erative. Always dim headlights when meeting
oncoming vehicles.
10. If the “Emergency Steering” light and/or “Low
Brake Pressure Warning” light (if equipped) illu-
minate during operation, steer the truck immedi-
ately to a safe stopping area, away from other
traffic if possible. Refer to item 7 above.
11. Check tires for proper inflation periodically during
shift. If truck has been run on a “flat”, or under-in-
flated tire, it must not be parked in a building
until the tire cools.
DYNAMIC RETARDING OPERATION
Dynamic Retarding is a braking torque (not a brake)
produced through electrical generation by the wheel-
motors when the truck motion (momentum) is the
propelling force. For normal truck operation, Dynamic
Retarding should be used to slow and control the
speed of the truck.
Dynamic Retarding is available in “Forward/Reverse”
at all truck speeds above 0 mph/kph; however, as the
truck speed slows below 3 mph (4.8 kph), the available
retarding force may not be effective. Use the service
brakes to bring the truck to a COMPLETE stop.
Dynamic Retarding will NOT hold a stationary truck on
an incline; use the Parking Brake or Wheel Lock brake
for this purpose.
Dynamic Retarding is available in “Neutral” only when
truck speed is above 3 mph (4.8 kph).
When dynamic retarding is in operation, the engine
RPM will automatically go to an advance RPM retard
speed setting (usually 900 - 1000 RPM*).
* NOTE: The exact engine speed in retarding may vary
due to the temperature of certain components; this is
controlled by the Propulsion System Controller.
Dynamic retarding will be applied automatically, if the
speed of the truck obtains the maximum truck speed
of 40 MPH (64 KPH). Any application of the Dynamic
retarding system (automatic, retarder lever, or foot
pedal) will cause an indicator light to illuminate in the
overhead display panel.
DYNAMIC RETARDER CONTROL LEVER
The Dynamic Retarder Control Lever mounted on the
right side of the steering column can be used to
modulate retarding effort. The lever will command the
full range of retarding and will remain at a fixed position
when released.
a. When the lever is rotated to full “Up” (counter-
clockwise) position, it is in the “Off/No Retard”
position.
b. When the lever is rotated to full “Down” (clock-
wise) position, it is in the full “On/Retard” position.
c. For long downhill hauls, the lever may be posi-
tioned to provide a desired retarding effort, and it
will remain where it is positioned.
NOTE: The Retarder Control Lever must be ro-
tated back to the “Off” position before the truck
will resume the PROPEL mode of operation.
The lever and foot-operated Retarder/Service Brake
pedal can be used simultaneously or independently.
The Propulsion System Controller (PSC) will deter-
mine which device is requesting the most retarding
effort and apply that amount.
DYNAMIC RETARDER/SERVICE BRAKE PEDAL
The Dynamic Retarder/Service Brake Pedal is a sin-
gle, foot-operated pedal which controls both retarding
and service brake functions. The first portion of pedal
travel commands retarding effort through a rotary po-
tentiometer. The second portion of pedal travel modu-
lates service brake pressure directly through a
hydraulic valve. Thus, the operator must first apply,
and maintain, full dynamic retarding in order to apply
A3-26 General Safety and Operating Instructions A03017