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If the hoist has been used under unfavorable working condition, handled roughly or become old,
like general machines, it shows various troubles and nonconformities.
All troubles and nonconformities cannot be described here. General troubles are listed below for
your reference.
Most of troubles not listed below are caused special factors. Regarding such troubles, consult
the nearest distributor or Mitsubishi Electric Hoist Corporation.
General troubleshooting
Problem
1. Touching the hoist or
pushbutton pendant
causes an electric
shock.
2. Operation in reverse
direction to that
indicated on
pushbutton.
3. Wire rope wears
badly.
4. Wire rope is wound
ununiformly.
General Troubleshooting
Cause
(1) I-beam or pushbutton pendant metallic casing
grounding failure
(2) Adhesion of paint to the I-beam surface
Leakage current increases due to high-frequency
component of inverter output voltage. The
rated sensitivity current of the earth-leakage
circuit breaker shall be 100 mA or more to
prevent unnecessary operations.
The circuit breaker is designed nor for
prevention of electrical shocks, but for
prevention of a fire caused by electrical leakage.
For this reason, remedies (1), (2), and (5)
described on the right side should be observed.
(3) Hoist or pushbutton pendant insulation failure
(4) Current leaking from other equipment or wiring
reaches the hoist through the I-beam.
(5) The floor conductivity is high.
•
The floor is wet with a highly conductive liquid,
such as water.
•
The hoist is on a highly conductive surface, such
as an iron plate, steel structure and surface plate.
(1) Incorrect connection of power supply line
(If the commercial power is used for traversing
operation)
Even if the power line is not connected correctly,
operation will not be performed in the opposite
direction.
(2) Wire rope wound reversely.
(1) The rope wears soon because it is frequently
pulled laterally and vertically.
(2) Disordered winding
(3) Use of wire rope other than parallel stranded rope (3) Replace the wire rope with a
(4) Wire rope oil not applied.
(1) Pulling laterally and vertically at too large angles
(Less than 10° for pulling laterally or less than 3°
for pulling vertically)
(2) Wire rope distorted
- 39 -
Remedy
(1) Ground completely.
100 Ω or less at 200 V
(2) Use the hoist suitable for the
ambient conditions
(waterproof type, etc.).
Remove paint completely.
(3) Check, and repair.
(4) Check, and repair.
(5) Install the hoist on a floor
with low conductivity, such as
a dry concrete floor.
(1) Exchange the phases R and T
of the power supply.
(2) Wind the rope correctly.
(1) Correct the using method.
(2) See Item 4.
proper one.
(4) Apply oil.
(1) Correct the using method.
(2) Replace.
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