Komatsu Galeo HD405-7R, Operation & Maintenance Manual

Page: 349 / 361

.
ATTACHMENTS, OPTIONS
ARSC (AUTOMATIC RETARDER SPEED CONTROL)
METHOD OF OPERATION
ACTUATION OF ARSC SYSTEM
The ARSC system is actuated when the auto retarder (ARSC) switch is ON.
When the set switch of the auto retarder (ARSC) set lever is pressed, the travel speed at that point is set as the
downhill travel speed. When traveling downhill, if the machine attempts to exceed the set travel speed, the retarder
is automatically actuated.
The set travel speed is displayed on the auto retarder set speed indicator and is saved in memory.
If the accelerator is depressed during operation of the ARSC, the ARSC is canceled and the speed increases.
If the brake pedal or retarder control lever are operated while the ARSC is being operated, it is possible to reduce
the speed or stop the machine in the same way as during normal operation of the brakes.
If the set travel speed is near the gear shifting point or there is a change in the grade of the slope, the transmission
may shift (shift up or shift down) even when the ARSC is being operated.
The time taken for the machine travel speed to match the set speed may differ according to the grade of the slope.
There may also be a slight difference between the set travel speed and the speed displayed on the speedometer.
METHOD OF SPEED SETTING
WARNING
If the speed is set to a speed that exceeds the maximum permissible speed obtained from the brake performance graph, there is
danger that there will be overheating and that the retarder brake may be damaged. Always set the speed so that it does not exceed
the maximum permissible speed.
If the actual machine speed during the setting operation is less than 10 km/h (6.2 MPH), the speed is set to 10 km/h
(6.2 MPH). If it is higher than 55 km/h (34.2 MPH), it is set to 55 km/h (34.2 MPH). In all other cases, it is set to the
actual travel speed.
The travel speeds that can be set depend on the selection of the gearshift lever as follows.
When the gearshift lever is at the D, 6, 5, 4, 3, 2, or L positions, the range for the set speed is 10 to 55 km/h (6.2 to
34.2 MPH).
It is impossible to set the speed when the gearshift lever is at the N or R positions.
METHOD OF CARRYING OUT FINE ADJUSTMENT OF SET TRAVEL SPEED
When it is desired to raise the set travel speed by 1 km/h (tap up), move the auto retarder (ARSC) set lever up once.
When it is desired to lower the set travel speed by 1 km/h (tap down), move the auto retarder (ARSC) set lever down
once.
REMARK
Release the auto retarder (ARSC) set lever after changing the set travel speed.
If the set switch and cancel are operated at the same time, the cancel operation is given priority.
If the set switch and tap up are operated at the same time, the tap up operation is given priority.
If the set switch and tap down are operated at the same time, the tap down operation is given priority.
The tap up and tap down operations are used for making fine adjustment of the set travel speed.
It is possible to adjust the set travel speed up to
±
5 km/h (3.1 MPH) when traveling in ARSC (when the accelerator
pedal is released). When the accelerator pedal is being depressed, the ARSC is canceled, so it is possible to
operate freely in a range from 10 to 55 km/h (from 6.2 to 34.2 MPH).
6 - 70