The success or failure of a transient voltage surge suppression (TVSS) device to protect your critical equipment is determined by the technology utilized within the component.
There are four standard technologies used by surge suppression devices:
- Gas Tube Arrestor
- Selenium Plates
- MOV (Metal Oxide Varistor)
- SAD (Silicon Avalanche Diode)
Utilizing the IEEE C62.41-1991 1.2X50 microsecond, 6000 volt wave form to evaluate the electrical characteristics of these technologies, the following results were determined.
MOV's
Metal oxide varistors are voltage dependent, nonlinear devices. Clamping voltage will vary with current and response-time is tens of nanoseconds. MOVs degrade at a rate relative to the magnitude and number of and current rating of surges. In testing, the MOV clamped at 340 Vpk and diminished to 240 Vpk in 40 nanoseconds. The variation in voltage is a function of the suppressed current.
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