Building Automation
Industrial Automation
Power Automation & Safety
Bangladesh Distributor
Limit Switches
 Introduction
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Features |
| Principles | Classifications |
| Engineering Data |
Further Information
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Explanation of Terms
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Troubleshooting |
| Problem | Probable cause | Remedy | |
| Mechanical failure | 1) The actuator does not operate. 2) The actuator does not return. 3) The actuator has been deformed. 4) The actuator is worn. 5) The actuator has been damaged. | The shape of the dog or cam is incorrect. | ・ 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 high. | ・ 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 operating position (with malfunctioning involved). | 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 mechanism. | |||
| The loosening of the mounting screws causing the position to be unstable. | |||
| The terminal part wobbles. (The mold part has been deformed.) | Overheating due to a long soldering time. | ・ 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 resulted. | ・ Use a temperature-resistive switch or change mounting positions. | ||
| Failures related to chemical or physical characteristics | Contact chattering | 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 penetration | 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. | |||
| Deterioration of the rubber part | The expansion and dissolution of the rubber caused by solvent or lubricating oil. | ・ Use an oil-resistant rubber or fluororesin bellows. ・ Use a weather-resistant rubber or protective cover. ・ Use a switch with a metal bellows protective cover. | |
| Cracks due to direct sunlight or ozone. | |||
| Damage to the rubber caused by scattered or heated cuttings. | |||
| Corrosion (rusting or cracks) | 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 characteristics | No actuation. No current breakage. Contact welding | Inductive interference in the DC circuit. | ・ 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. | ||
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