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Joined: Jul 2001
Posts: 311
F
Member
I'm trying to find an article about the importance of TVSS. I looked at EC&M, IAEI and Electrical Contractor magazines online and thought I could do a search but I couldn't. I remember reading one of them late last year with an excellent article in in. Can anyone remember?

Joined: Jan 2003
Posts: 73
C
Member
Don't know if this is what your looking for as to what detail but might help. http://www.ecmweb.com/ar/electric_demystifying_tvss/

Joined: Apr 2002
Posts: 2,527
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Moderator
Another site that has discussed TVSS application is the online version of [no longer published] Power Quality magazine. I believe their owner is also a parent of EC&M.

Joined: Mar 2003
Posts: 16
D
Member
The best application data is from IEEE document C61.42-1991. Unless the devices are properly sized, located, and installed they are worthless.

The IEEE document will define class C, B, and A devices, there location specifics, sizes, and most importantly the installation specifications.

Joined: Apr 2002
Posts: 2,527
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DBC1, the standard may be IEEE C62.41-1991 Recommended Practice for Surge Voltages in Low-Voltage AC Power Circuits

Fair warning — This is a heavy-duty text; not for the casual reader. [$150]




[This message has been edited by Bjarney (edited 05-04-2003).]

Joined: Mar 2003
Posts: 16
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Bjarner, oops a little dyslexia problem. It is C62.41

Joined: Jul 2001
Posts: 311
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DBC1-

In general, how is a TVSS sized?

Joined: Mar 2005
Posts: 1,213
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Member
Originally Posted by Frank Cinker
DBC1-

In general, how is a TVSS sized?
It's funny, I'm wondering the exact same thing, nearly 4 years later. Near as I can tell, every TVSS on the market is oversized about 10-100x greater than the most powerful transients experienced short of a nuclear HEMP attack; I imagine it's just a natural byproduct of sizing MOVs for clamping voltage, and many places don't even mention the Joule rating. Oversizing by 10x does seem to increase longevity, though- an 8J module might protect against 1 bad lightning strike, but an 800J module will take them repeatedly and never burn out. So... so long as it's got the right voltage and KAIC rating, it's going to protect your system.

I have those IEEE reports, btw- the one most often cited is merely a report of measured transient reponses and more useful for people designing TVSSs than people trying to figure out which one to buy.


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