Analysis Of The Causes And Contact Material Applications Of Electromagnetic Relays During High-Frequency Operation

Electromagnetic relays in automated production lines and pulse control equipment often experience prolonged high-frequency reciprocating operation, easily leading to their casings becoming extremely hot to the touch. Maintenance personnel often struggle to distinguish whether the heat originates from the coil or the conductive contacts, resulting in misdiagnosis and significantly increased maintenance costs. The contacts are the core components carrying the load current. Using stable Silver Copper Composite Rivet Contacts can reduce the fundamental risk of continuous overheating in the contact circuit from the source. Coil heating is continuous Joule heating, generating stable heat upon energization. Contact heating, on the other hand, accumulates with each pulse of switching on and off; interrupting the arc further exacerbates the temperature rise. The heating logics of the two are clearly different.

On-site, a simple touch test can be used to initially identify the heat source. After the equipment is running stably, gently touch different areas of the relay casing. The coil is usually located at the bottom or side of the casing. If the temperature in this area is significantly higher, it is likely due to abnormal coil voltage or poor heat dissipation. If the high temperature is concentrated at the wiring terminals, contact circuit losses are the primary cause. Inferior contacts are prone to increased contact resistance due to arc erosion. Conductive terminals made of Composite Contact Rivets for Relay effectively suppress the continuous increase in contact resistance over time, reducing additional temperature rise caused by current loss.

To accurately determine the source of heat, infrared thermography and thermal imaging equipment can be used to scan the temperature distribution of the casing. A clear temperature difference will appear between the coil and contact areas, with the high-temperature area directly corresponding to the faulty heat source. Step-by-step no-load testing is a more reliable method of identification. Operating with only the coil connected and the load disconnected, the casing heat is generated solely by the coil; a sudden temperature rise after connecting the load indicates that current loss at the contacts is contributing to heat generation. Under high-frequency operating conditions, repeated arcing of the contacts causes rapid wear of ordinary materials. Silver Cadmium Electrical Contact, with its silver-copper composite structure, has a much higher resistance to arc impact than single-metal contacts.

Coil overheating faults are often caused by excessive supply voltage, poor heat dissipation in enclosed spaces, and current surges caused by frequent switching on and off. Troubleshooting only requires checking the control power supply parameters and improving the equipment's ventilation. Overheating of contacts is caused by a more complex set of factors. Exceeding the rated load current, surges from capacitive loads, and increased contact resistance due to oxidation and erosion can all exacerbate heat generation. During maintenance and testing, the contact closure voltage drop can be measured. The standard value should be controlled within tens of millivolts. An excessive voltage drop indicates severe contact wear, and replacing the contacts with AgCdO Bimetal Silver Rivet Contacts suitable for the operating conditions can quickly restore contact conductivity.

While overheating of the relay casing is not always a fault, prolonged overheating accelerates internal insulation aging and shortens the overall lifespan of the device. Accurately identifying the heat source is a prerequisite for efficient maintenance. Coil faults only require adjustments to power supply and cooling conditions, while contact degradation necessitates replacing conductive components suitable for high-frequency operating conditions. The repair methods for these two issues are completely different; confusing the fault point will result in unnecessary replacement of parts. In high-frequency start-stop and high-current pulse equipment, the mass production of Contact Electrical Bi-metal Contact Rivets materials can stably control contact temperature rise over the long term, reducing the frequency of relay overheating faults and minimizing production line downtime maintenance costs.

Addressing the high-temperature challenge of various high-frequency relays, our self-developed and mass-produced Silver Copper Composite Rivet Contact combines high conductivity, arc resistance, and low contact resistance. It is compatible with various inductive, capacitive, and resistive loads, significantly delaying contact oxidation and erosion, and stabilizing contact temperature rise. Suitable for automated production lines, pulse control, and other high-frequency equipment across all scenarios, it completely solves the relay housing overheating problem caused by contact heating from the material perspective. For contact material selection or bulk purchasing needs, please feel free to contact us for sample testing and pricing.