Komatsu HD785-5, Operation & Maintenance Manual

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ATTACHMENTS, OPTIONS
ARSC (AUTOMATIC RETARDER SPEED CONTROL)
METHOD OF OPERATION
ACTUATION OF ARSC SYSTEM
The ARSC system is actuated when the system switch is ON.
If the set switch on the ARSC set lever is pressed, the travel speed at that moment is set as the downhill travel
speed. If the travel speed exceeds the set downhill speed, the retarder is automatically actuated.
The set travel speed is displayed on the set travel speed display and is stored in memory.
If the accelerator pedal is pressed while the ARSC is being operated, 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 machine speed or stop in the same way as during normal brake operations.
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). 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 shift lever is at the D, 5, 4, 3, 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 shift lever is at the N or R positions.
METHOD OF CARRYING OUT FINE ADJUSTMENT OF SET TRAVEL SPEED
To raise the set travel speed 1 km/h (0.6 MPH), push the ARSC set lever forward once.
To decrease the set travel speed 1 km/h (0.6 MPH), pull the ARSC set lever back once.
REMARK
Release the ARSC set lever after changing the set travel speed.
If the set and cancel operations are carried out at the same time, the cancel operation is given priority.
If the set and tap up operations are carried out at the same time, the tap up operation is given priority.
If the set and tap down operations are carried out 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 adjust
the set speed freely in a range from 10 to 55 km/h (from 6.2 to 34.1 MPH).
METHOD OF INCREASING SET TRAVEL SPEED
If it is desired to increase the set speed, depress the accelerator pedal to increase speed, and when the desired set
travel speed is reached, press the set switch on the ARSC set lever. The set travel speed will be changed to the new
speed.
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