Komatsu Galeo PC138US-8, Руководство по ремонту

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SEN02468-01 40 Troubleshooting
22
PC138US, USLC-8
H-21 Swing acceleration or swing speed is low 1
Trouble • Swing acceleration or swing speed is low.
(1) Swing acceleration or swing speed is low in both
directions.
Related
information
• Conduct the troubleshooting in working mode P.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1
Malfunction of swing control
valve (pressure compensa-
tion valve)
The pressure compensation valve of the swing control valve may
have a malfunction. Check it directly.
2
Malfunction of swing motor
(holding brake) The holding brake of the swing motor may have a malfunction.
Check it directly.
3 Swing motor defective
a
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
Left work equipment control
lever
Leakage from swing motor
Swing circuit relieved Below 6
l
/min
4 Swing machinery defective
The swing machinery may have a defect in it. Check it directly. (It
may be checked by abnormal sound, abnormal heating, metal
chips in drain oil, etc.)
Trouble • Swing acceleration or swing speed is low.
(2) Swing acceleration or swing speed is low in only
one direction.
Related
information
• Conduct the troubleshooting in working mode P.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1
Malfunction of swing PPC
valve
a
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
Left work equipment control
lever
PPC valve output pressure
In NEUTRAL 0 MPa {0 kg/cm
2
}
Operated for swing
Above 2.7 MPa
{Above 28 kg/cm
2
}
2
Malfunction of swing control
valve (spool) The spool of the swing control valve may have a malfunction.
Check it directly.
3
Defective adjustment or mal-
function of swing motor
(safety valve)
a
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
Swing lock switch
Left work equipment
control lever
Swing relief pressure
(Pump pressure)
ON
Swing circuits
relieved (separately
on both sides)
29.2 ± 1.5 MPa
{298 ± 15 kg/cm
2
}
4
Defective sealing of swing
motor (suction valve) Sealing of the suction valve of the swing motor may be defective.
Check it directly.
5
Malfunction of swing motor
(reverse prevention valve) Sealing of the reverse prevention valve of the swing motor may be
defective. Check it directly.