Page top

Lead Contents

Limit Switches

Introduction Features
Principles Classifications
Engineering Data Further Information
Explanation of Terms Troubleshooting

Related Contents

Primary Contents

ProblemProbable causeRemedy
1) The actuator
does not operate.
2) The actuator
does not return.
3) The actuator
has been
4) The actuator
is worn.
5) The actuator
has been
The shape of the dog or cam is
・ Change the design of the dog or cam and
smooth the contacting surface of the cam.
・ Scrutinize the suitability of the actuator.
Make sure that the actuator does not bounce.
The contacting surface of the
dog or cam is rough.
The actuator in use is not suitable.
The operating direction of the
actuator is not correct.
The operation speed is excessively
・ Attach a decelerating device or change the
mounting position of the Switch.
Excessive stroke.・ Change the stroke.
The rubber or grease hardened due
to low temperature.
・ Use a cold-resistive switch.
The accumulation of sludge, dust,
or cuttings.
・ Change to a drip-proof switch or one that
provides a high degree of protection.
・ Use a protection cover and change the
solvent and materials.
Dissolution, expansion, or swelling
damage to the rubber parts of the
driving mechanism.
There is a large
deviation in
position (with
Damage to and wear and tear of the
internal movable spring.
・ Regularly inspect the Switch.
・ Use a better quality switch.
・ Tighten the mounting screws securely.
Use a mounting board.
Wear and tear of the internal
The loosening of the mounting
screws causing the position to be
The terminal
part wobbles.
(The mold part
has been
Overheating due to a long soldering
・ Solder the Switch quickly.
・ Change the lead wire according to the carry
current and ratings.
The Switch has been connected to
and pulled by thick lead wires with
excessive force.
High temperature or thermal shock
・ Use a temperature-resistive switch or
change mounting positions.
related to
chemical or
Vibration or shock is beyond the
rated value.
・ Attach an anti-vibration mechanism.
・ Attach a rubber circuit to the solenoid.
・ Increase the operating speed (with an
accelerating mechanism).
Shock has been generated from a
device other than the Switch.
Too-slow operating speed.
Oil or water
The sealing part has not been
tightened sufficiently.
・ Use a drip-proof or waterproof switch.
・ Use the correct connector and cable.
(Use a sealed connector for sealed switches.)
The wrong connector has been
selected and does not conform
to the cable.
The wrong switch has been selected.
The terminal part is not molded.
The Switch has been burnt or
carbonated due to the
penetration of dust or oil.
of the rubber
The expansion and dissolution of
the rubber caused by solvent or
lubricating oil.
・ Use an oil-resistant rubber or fluororesin
・ Use a weather-resistant rubber or protective
・ Use a switch with a metal bellows protective
Cracks due to direct sunlight or
Damage to the rubber caused by
scattered or heated cuttings.
(rusting or
The oxidation of metal parts
resulted due to corrosive solvent
or lubricating oil.
・ Change the cutting oil or mounting position.
・ Use a crack-resistant material.
The Switch has been operated in
a corrosive environment, near the
sea, or on board a ship.
The electrical deterioration of
metal parts of the Switch resulted
due to the ionization of cooling
water or lubricating oil.
The cracking of alloyed copper due
to rapid changes in temperature.
Failures related
to electric
No actuation.
No current
Contact welding
Inductive interference in the DC
・ Add an erasing circuit.
Brown powder generated due to
switching operations
・ Use a switch with a special alloy contact or
use a sealed switch.
A short-circuit or contact weld
due to contact migration.
・ Reduce the switching frequency or use a
switch with a large switching capacity.
Contact weld due to an incorrectly
connected power source.
・ Change the circuit design.
Foreign materials or oil penetrated
into the contact area.
・ Use a protective box.