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Building Automation


Industrial Automation


Power Automation & Safety

Bangladesh Distributor

Lead Contents

Basic Switches

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

Related Contents

Primary Contents


Location
of failure
FailurePossible causeCorrective action
Failures
related to
electrical
characteristics
ContactContact
failure
・ Dust and dirt on the contacts.・ Remove the cause of the problem, place the switch in a box, or use a sealed switch.
・ Water or other liquid has penetrated into a switch.
・ Chemical substances have been generated on the contact surface due to the atmosphere containing chemical corrosive gas.・ Use a switch having contacts with high environmental resistivity (such as gold or alloy contacts).
・ Chemical substances have been generated on the contact surface when the switch switches a very low load.
・ Solder flux has penetrated into the switch.・ Review the soldering method.
・ Silicon gas exists near the switch.・ Remove the material generating gas, or adjust contact capacity to prevent formation of silicon compounds on the contacts.
Malfunction・ The contacts are separated from each other by vibration or shock.・ Use a switch having a high contact force (generally a high OF).
Contact
welding
・ The load connected to the switch is too high.・ Switch the load with a high-capacity relay or magnetic relay or insert a contact protection circuit.
Insulation
degradation
(burning)
・ Contacts have been melted and scattered by arc.・ Switch the load with a high-capacity relay or magnetic relay.
・ Water has penetrated into the switch because the switch has been used in an extremely hot environment.・ Remove the cause of the problem, place the switch in a box, or use a sealed switch.
・ Liquid has penetrated into the switch and been carbonized by arc heat.
Failures
related to
mechanical
characteristics
ActuatorOperating
failure
・ The sliding part of the actuator has been damaged because an excessive force was applied on the actuator.・ Make sure that no excessive force is applied to the actuator, or use an auxiliary actuator mechanically strong.
・ Foreign material like dust, dirt and oil has penetrated into the switch.・ Remove the cause of the problem or place the switch in a box.
・ The actuator does not release because the operating body is too heavy.・ Use a switch having a higher OF.
・ The switch is loosely installed and thus does not operate even when the actuator is at the rated OP.・ Secure the switch.
Low
durability
・ The shape of the dog or cam is improper.・ Change the design of the dog or cam.
・ The operating method is improper.
・ The operating speed is too high.
・ Review the operating stroke and operating speed.
Damage・ Striking or other excessive shock has been applied to the actuator.・ Remove the cause of problem or use a switch mechanically strong.
・ The caulked part is not good enough or the assembled condition is poor.・ Replace the switch with a new one.
・ Deformation or drop-out
・ Actuator was subjected to an excessive force and force from an inappropriate direction.
・ Review the handling and operating method.
Mounting
section
Damage・ Screws have not been inserted straight.・ Check and correct screw insertion method.
・ The mounting screws were tightened with too much torque.・ Tighten the screws with an appropriate torque.
・ The mounting pitch is wrong.・ Correct the pitch.
・ The switch is not installed on a flat surface.・ Install the switch on a flat surface.
TerminalDamage・ An excessive force was applied to the terminal while being wired.・ Do not apply an excessive force.
・ The plastic part has been deformed by soldering heat.・ Reduce the soldering time or soldering temperature. (Refer to the information given under Safety Precautions for that model.)