105
Electromagnetic Contactor, Relay
Symptom Cause Remedy Main factor Countermeasure
Electric chain hoist
does not stop
Electromagnetic
Contact point
welding, or fusing
Operate the contactor manually to check
the conduction.
When the contact point is welded or
fused, replace the contactor.
When the device is a miniature relay,
check the contact point visually.
Excessive inching or
plugging operation
(consecutive
impression of start
rush current)
Do not perform
excessive operation.
Over voltage Operate the electric
chain hoist with the
rated voltage.
Over current due to
over load
Use the electric chain
hoist with a load less
than the capacity.
Electric chain hoist
does not operate.
Burnout or
breakage of relay
coil or contactor coil
Measure the resistance of relay coil or
contactor coil. If it is infinity, replace the
relay or the contactor.
Excessive inching or
plugging operation
(consecutive
impression of start
rush current)
Do not perform
excessive operation.
Over voltage Operate the electric
chain hoist with the
rated voltage.
Chattering due to low
voltage (consecutive
impression of start
rush current)
Operate the electric
chain hoist with the
rated voltage.
Damaged moving
parts
Operate the Electromagnetic contactor
by its manual operation part. Replace the
contactor if it does not move smoothly.
Check the miniature relay visually if it
does not have damaged part.
Vibration, impact Use the electric chain
hoist avoiding the
impact.
Fuse
Symptom Cause Remedy Main factor Countermeasure
Electric chain hoist
does not operate.
(Electromagnetic
Contactor does not
operate.)
Blown out Check the conduction of the fuse. When
no conduction, check the cause and then
replace the fuse.
Short circuit of the
control circuit, burnout
of electrical part
Refer to the items
related to the electrical
part in failure.
Over current due to
defective operation
of Electromagnetic
contactor
Refer to the items
of Electromagnetic
Contactor.
3
Troubleshooting Electromagnetic Contactor, Relay / Fuse
(to be continued)