29
Chapter X Faults and Troubleshooting
Fault
phenomenon
Reasons
Troubleshooting
Motor
fails
to
rotate upon rising
1. There is wire break of button switch.
2. Short-circuit occurs in coil of AC
connector occurs.
3. Limit switch is damaged
1. Inspect the circuit of button switch
2. Inspect the circuit of AC connector
3. If the faults are eliminated after the
terminals connecting limit switch is short
connected via wire, such limit switch and shall
be inspected. Meanwhile, limit switch shall be
adjusted or replaced.
4. Replace limit switch
Motor generates
sound but fails to
rotate
Default phase of three-phase supply
The rotation shall be stopped immediately.
Meanwhile, the inspection on major loop of
motors shall be performed to check whether
wire break or loss of loop occurs in such loop.
Motor can rotate
but the working
platform fails to
rise.
1. Incorrect motor direction of turning.
2. Insufficient hydraulic oil.
3. Air is filled in the pump due to
transport and other reasons, making
air-plugging phenomenon occur.
4. Overflow is out of work
5. The oil return solenoid valve plug is
jammed with dirt.
6. The sealing of oil outlet of oil pump is
damaged.
7. The work of motors is heavy and
vibratory. Outside screen of oil filter is
seriously jammed.
1. Change phase sequence of motors.
2. Supplement and discard hydraulic oil.
3. Remove one-way valve, and the inching
rises (attention shall be paid to oil injection).
Upon the oil flowing out of the hole, the
one-way valve shall be well assembled
(tighten up).
4. Inspect the condition of sealing and sealing
elements of overflow valve plug; clean valves
or replace damaged seal ring.
5. Inspect oil return solenoid valve and clean
valve plug.
6. Gear pump can be removed to inspect and
replace seal rings.
7. Clean filter.
Rising velocity is
too slow
Oil leakage phenomenon occurs due to
the damage to oil outlet of oil pump
See above
Upon
operation,
the
vibratory
phenomenon
occurs.
1. Air exists in hydraulic circuit.
2. Air leakage exist in upper connector
of oil suction pipe of oil pump.
3. Filter is jammed.
1. Vent by operating up and down repeatedly.
2. Check the connecting and sealing condition
of the oil suction pipe.
3. Clean oil filter.
Lifter can rise but
fail to fall
1. Poor contact of the internal button
switch.
2. Lock cylinder fails to be separated
from the plate.
3. The clearance between the column
and beam is too narrow.
1. Disassemble to remove the problem.
2. Shorten the lock cylinder rod to lock cylinder
to get rid of the square rack when the lock bar
is placed in the locking position.
3. Adjust the clearance between the column
and the beam.
