Komatsu HM400-5, Operation & Maintenance Manual

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1.
Return accelerator pedal (1) before entering a downhill
slope.
2.
Operate retarder control lever (2) to decelerate the ma-
chine.
3.
Move the gear shift lever to the position (5, 4, 3, 2) that
matches the maximum permitted speed on the brake per-
formance curve.
4.
When traveling downhill, operate retarder control lever (2)
to set the engine speed to above 1800 rpm and drive the
machine so that the indicator of the retarder oil tempera-
ture gauge comes within the white range.
BRAKE PERFORMANCE CURVE
How to read the graph
Example) Downhill distance: 1500 m
Traveling resistance: –11 % (Grade resistance: –13 %, rolling resistance: 2 %)
Payload: 40 t
Obtain the maximum permissible speed and the gear speed range from the graph when traveling downhill under
the above conditions.
1.
Use the brake performance curve for downhill distance of 1500 m.
2.
Starting from point (A) which corresponds to the gross machinery weight, draw a perpendicular line down.
3.
Take the point where it crosses the line for travel resistance 1500 m as (B) and draw a horizontal line.
OPERATION MACHINE OPERATIONS AND CONTROLS
3-191