KITO ER2 - Upper;Lower Limit Switch

106
Troubleshooting (continued)
Upper/Lower Limit Switch
Symptom Cause Remedy Main factor Countermeasure
Electric chain hoist
does not operate.
(Electromagnetic
Contactor or VFD
does not operate.)
Contact point fusing Actuate the limit switch manually to
check the conduction of the contact
points.
Replace the limit switch as a whole when
no conduction.
Habitual use of the limit
switch
Do not use the limit
switch habitually.
Breakage Check the wiring. Repair or replace the
limit switch as a whole if the limit switch
has no conduction.
Vibration, impact Use the electric chain
hoist avoiding the
impact.
Moving part rusted
shut (defective
return action of the
moving part)
Check the moving part of the limit switch
such as actuator lever is not stiff. If it is
stiff, remove the rust or replace the stiff
part.
Leaving the electric
chain hoist for a long
time at the upper/lower
limit.
Do not leave the
electric chain hoist at
the upper/lower limit.
Electric chain hoist
does not stop at the
upper/lower limit.
Contact point
welding
Actuate the limit switch manually to
check the conduction of the contact
points.
Replace the limit switch as a whole when
it does not turn off.
Habitual use of the limit
switch
Do not use the limit
switch habitually.
Moving part rusted
shut
Check the moving part of the limit switch
such as actuator lever is not stiff. If it is
stiff, remove the rust or replace the stiff
part.
No use for a long time,
use in an environment
with rich moisture
Check the electric
chain hoist regularly.
Wrong wiring Check the wiring in accordance with
the wiring diagram. Perform the wiring
correctly.
If the wiring of the limit switch is correct,
the cause is in the negative phase
connection. Change two wires of the
power line.
Wrong wiring Correct the wiring in
accordance with the
wiring diagram.
Chapter 3 Troubleshooting
3
Upper/Lower Limit Switch Troubleshooting