SELENIUM SURGE SUPPRESSORS

A selenium surge suppressor, also known as a selenium surge arrester or selenium surge diverter, was a type of electrical component used in the past for protecting electrical and electronic equipment from voltage spikes and surges in power lines. It was designed to divert or absorb excessive voltage transients, thus safeguarding connected devices from potential damage.

Here are some key points about selenium surge suppressors:

1. Material: Selenium surge suppressors were constructed using the element selenium, similar to selenium rectifiers. Selenium had certain electrical properties that made it suitable for this application.
2. Operation: When a voltage surge or transient occurred in the power supply, the selenium surge suppressor would conduct, providing a low-resistance path for the excess current. This would divert the surge away from the protected equipment, limiting the voltage that reached sensitive devices.
3. Advantages: Selenium surge suppressors had some advantages, including their ability to handle high surge currents and their robustness in harsh environments. They were used in older electrical systems where modern surge protection technologies were not available.
4. Disadvantages: These devices also had significant drawbacks:
   • Inefficiency: Selenium suppressors had a relatively high “clamping” voltage, which means they allowed a significant voltage increase before conducting, potentially allowing some voltage spikes to reach equipment.
   • Slow response: They were slower to respond to surges compared to modern surge protection devices like metal-oxide varistors (MOVs) or transient voltage suppressors (TVS).
   • Toxicity: Selenium is a toxic element, and there were safety concerns related to its use in electrical components.
5. Obsolete: Selenium surge suppressors have become obsolete and are no longer used in modern electrical systems. They have been replaced by more efficient and safer technologies such as MOVs, TVS diodes, gas discharge tubes, and other surge protection devices.

Modern surge protectors use semiconductor-based components that can respond quickly to voltage spikes and provide better protection for sensitive electronic equipment. These newer devices are also more cost-effective and do not pose the same environmental or safety risks associated with selenium.