Maeda MK0003, Service Manual, Page: 338 / 348

6-10
1.3.3 FAILURE CAUSE AND COUNTERMEASURE
● Trouble of winch motor
Symptom Cause Remedy
A. There are abnormal noise and
vibration.
1. Air remains in the circuit and
motor.
2. Cavitation
(occurrence of negative
pressure)
• Completely bleed air from the
circuit. When the motor
generates negative pressure,
the air in the case is sucked.
Therefore, air may not bled
completely. Inspect the drain
piping.
• Restudy the hydraulic circuit
and take measures to prevent
the occurrence of negative
pressure.
B. Normal rotational speed
cannot be achieved.
3. Insufficient flow rate of oil
4. Overheat, increase in leak
amount due to inappropriate
viscosity of hydraulic oil
5. Failure in the motor
• Study the supply circuit such
as the pump circuit and leak
from the relief valve and
eliminate the cause.
• Eliminate the cause.
• Replace the motor. (Check an
outside drain amount of the
motor. If the drain amount is
normal, there is often other
cause.)
C. Normal torque cannot be
achieved.
6. Normal pressure is not
generated due to an error in the
circuit on the motor inlet side.
7. Abnormally high pressure is
generated in the circuit on the
motor outlet side.
8. Increase in leak amount due to
overheat
9. Failure in the motor
• Study the supply circuit such
as the pump circuit and relief
valve and eliminate the cause.
• Study the return side circuit
and eliminate the cause. For
example, clogging of circuits,
clogging of the return filter or
reverse installation
• Eliminate the cause.
• Replace the motor.
* In general, inspection of an outside drain amount is very effective for trouble shooting of the motor. Empirically, if
the outside drain amount is normal, the motor has no abnormality in many cases.
1.3.4 PRECAUTIONS IN WINCH MOTOR
1. Gear oil change timing
(1) First change (first change after operation start) : 500 hours
(2) Second time onward
: Every 1000 hours or yearly
However, if gear oil decreased for some reason, check the cause, take measures and replenish gear oil.
Gear oil change quantity: 0.75L