Maeda MC815C - Abnormal Sound Generated at a Stop of Slewing Is Loud; Impact at a Stop of Slewing Is Significant; Natural Descending Amount at Slewing Is Significant

T-430
H-27 [Significant jolt on slewing stop]
Content Impact at a stop of slewing is significant
Assumed cause
and action to be
taken
Cause Diagnostic method and action to be taken
1
Crane control valve - slew
operation valve (spool)
malfunction
• Check for malfunction in crane control valve - slew operation
valve spool
Slew lever: at neutral
Output pressure: 0 Mpa [0 kg/cm
2
]
Slew lever: when operating
Pilot pressure: 3.1 Mpa [32 kg/cm
2
] or more
2 Slewing reducer fault
• Check for slewing reducer malfunctions
(May be assessed by presence of abnormal sounds or
heating, metal powder contamination in lubricating oil, etc.)
H-28 [Abnormal noise at the stop of slewing is significant]
Content Abnormal sound generated at a stop of slewing is loud
Assumed cause
and action to be
taken
Cause Diagnostic method and action to be taken
1
Crane control valve - slew
operation valve (spool)
malfunction
• Check for malfunction in crane control valve - slew operation
valve spool
Slew lever: at neutral
Output pressure: 0 Mpa [0 kg/cm
2
]
Slew lever: when operating
Pilot pressure: 3.1 Mpa [32 kg/cm
2
] or more
2 Slewing reducer fault
• Check for slewing reducer malfunctions
(May be assessed by presence of abnormal sounds or
heating, metal powder contamination in lubricating oil, etc.)
3 Slewing bearing fault • Check for slewing bearing malfunctions
H-29 [Natural descending amount at slewing is significant]
Content Despite the slewing motor brake operating, the natural descending amount on slewing is significant
Assumed cause
and action to be
taken
Cause Diagnostic method and action to be taken
1
Crane control valve - slew
operation valve (spool)
malfunction
• Check for malfunction in crane control valve - slew operation
valve spool
Slew lever: at neutral
•
Check if output pressure is 0 Mpa [0 kg/cm
2
]
Pin brake release pressure 0.5 Mpa [5 kg/cm
2
] + drain line
pressure
Slew lever: when operating
Pilot pressure: 3.1 Mpa [32 kg/cm
2
] or more
2
Operation fault of slewing
motor
• Check for malfunction of slewing motor pin brake parts
★
Stop engine to perform preparations and conduct diagnosis
at a high engine idling speed.
Operation lever at slew relieving
Slewing motor leakage rate: 6 L/min or less
3 Is there an overload?
• Check if the inclination angle of the hoisted load is within 3
degrees
[Additional information]
• With the slewing motor in its normal position, it is fixed by the slewing motor pin brake.