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3) Hook lowers
but will not
raise.
a) Excessive load mechanical load clutch slipping.
a) Refer to installation instruction in
chapter 4.
b) Open hoisting circuit-open or shorted winding in
reversing contactor coil loose connection or
broken wire in circuit; control station contacts not
making; upper limit switch contacts open.
b) Check electrical continuity and
repair or replace defective part.
c) Phase failure.
c) See item 1b
4) Hook raises
but will not
lower.
a) Open control circuit
– "down" contactor coil
broken or short-circuited; "down" limit switch
broken.
a) Check electrical continuity and
repair or replace defective part.
5) Hook lowers
when hoisting
control is
operated.
a) Phase failure
a) See item 1B
b) Phase reversal.
b) Refer to installation instruction in
chapter 3.
6) Hook does
not stop
promptly
a) Brake slipping.
a) Check brake.
b) Excessive load.
b) See item 1H
7) Hoist
operates
sluggishly
a) Excessive load
a) See item 1H
b) Low voltage
b) Correct low voltage condition.
c) Phase failure or unbalanced current in the
phases.
c) See item 1b.
d) Brake dragging.
e) Check brake.
8) Motor
overheats.
a) Low voltage.
a) Correct low voltage conditions.
b) Excessive load.
b) See item 1H.
c) Extreme external heating.
c) Above an ambient temperature of
40°C (104°F) the frequency of hoist
operation must be limited to avoid
overheating
of
motor.
Special
provisions
should
be
made
to
ventilate the space or shield the hoist
from radiation.
d) Frequent starting or reversing.
d) Avoid excessive inching, jogging or
plugging. This type of operation
drastically shortens the motor and
contactor life and causes excessive
brake wear.
e) Phase failure or unbalanced current in the
phase.
e) See item 1B.
f) Brake dragging.
f) Check brake.
9) Hook fails to
stop at either or
both ends of
travel.
a) The limit switches do not open the circuits
because they are stuck. Limit switches not
adjusted correctly.
a) Check
switch
connections,
electrical continuity and mechanical
operation.
Check
the
switch
adjustment of Limit Switches.
b) Limit switch shaft not rotating.
b) Check for damaged Limit Switch
gears and their fixing.
c) Travelling nuts not moving along shaft-guide
plate loose; shaft or nut threads damaged.
d) Tighten
guide
plate
screws.
Replace damaged part.
10) Hook
stopping point
varies.
a) Limit switch not holding adjustment.
a) see item 9.
b) Brake not holding.
b) check the brake.
Table 20:
“Troubleshooting based on hoist behaviour”
