Komatsu GD555-5 Operation & Maintenance Manual page 210

OPERATION
SAFETY DEVICE OF BLADE
A slip clutch is installed to the circle to prevent accidents when an abnormal impact load is applied to the end of the
blade during work.
If any problem occurs in the slip clutch, the following problems may appear, so please contact your Komatsu
distributor for repairs and adjustment.
Examples of failure
When operating the blade rotation control lever, the circle does not rotate.
Even if the motor is running, the clutch is slipping and the circle does not rotate.
-> As the clutch is likely to burn, adjustments are necessary.
The hydraulic system is in relief state and the circle does not rotate.
-> This is normal. However, if the slip torque is in maximum or excessively high, the clutch may be damaged.
OPERATION
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