On 7/6/13 6:22 AM, James Wolf wrote:
Through my occupation, I talk frequently to the Transector Rep. He tells
me that over time (< 5 years) MOV's lose their effectiveness. I've not
heard this before. If this is true, need to get on that.
MOVs are notorious for this. Each time they clamp a transient, they die
a little bit. It's a real problem for MOVs used in line voltage
applications, when too low of a voltage is selected (e.g. 130Vrms for
120V use) and the normal transients that one sees gradually kills the
MOV. Eventually, the device fails: either open (providing no
protection) or shorted (blowing fuses or causing fires).
Gas or vacuum gap is what you really want in an environment likely to
see many transients (and I think antennas fit in that bucket).
Standler's book on transient suppression (and the website) are a good
resource. $20 well spent. http://www.amazon.com/dp/0486425525
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