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Sci.Electronics.Basics -> Surge / Ground / Lightning
There are 215 messages in this thread.
You are currently looking at messages 100 to 120.
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Author: w_tomDate: 00:17 05-05-08
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On May 4, 11:35 am, Mike Tomlinson <m...@jasper.org.uk> wrote:
> ...
> The same thing said eight times. Part of w_tom's modus operandi -
> repeat something enough times and it must be true.
If must be said eight times - and still not understood by trader -
because that is the point. He does not want to understand it.
BTW, prim and proper Englishmen insist we must never mix first,
second, and third person. They don't worry about being misinterpreted
since misinterpretation is part of being prim and proper.
Better is to mix first and third person often so that the only
thing important - the message - cannot be misconstrued. If he chooses
to do so, no problem. If w_tom chooses to do so, no problem. If I
choose to do so, no problem. Exact same meaning to everyone except
the prim and proper Englishman who would now get all caught up in a
tizzy.
No problem. trader still will deny a fact stated eight times.
All appliances contain internal protection. That protection is not
provided by MOVs no matter how many times trader says otherwise.
Protection that may be overwhelmed if the typically destructive surge
is not earthed by a 'whole house' protector. Facts remain no matter
which person is used.
Again, referring to trader's latest myth: increasingly complex
electronics now contain even better protection than those earlier,
less complex electronics. Today, international standard now require
signal interface ICs to withstand 2000 and 15,000 volts without
damage. Previous interfaces in less complex electronics could only
withstand 30 or 40 volts. trader should have known these numbers long
before he posted more myths. Increasing complex electronics are even
more robust - less likely to suffer surge damage. But again, trader
knew long before learning any facts.
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Author: w_tomDate: 00:37 05-05-08
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On May 4, 1:24 pm, "Tantalust" <Tantal...@paradise.net> wrote:
> Why do you have this pompous attitude; constantly sermonizing down to peop=
le
> as if they're your little, personal kindergarten class?
Ask polite or technical questions, and get straight honest
responses. If you think my tone was offensive, then review your
original post. Post like an emotional child and get a stern response.
Franc Zabkar asked a question without an incendiary intent.
Therefore a straight and honest answer. My posts to you was blunt and
honest. How blunt? It did not contain a single insulting statement or
implication. It was a hard straight answer - nothing more. And it was
appropriately terse where you make claims or denial without any
supporting facts. If you need sweet words, go find a spouse. Was
your question incendiary or based in technical curiosity?
You were neither mocked nor insulted. Your technical mistakes were
corrected accurately. Neither your emotions nor your children have a
place here. This is a technical discussion about an unpopular reality
=96 about facts known even 100 years ago and that contradict both
popular urban legend and retail store propaganda.
Nobody - you, me, or anyone else (should) cares about your
emotions. Your emotions don't belong in a technical discussion. You
were not mocked or insulted - just technically replied to. You don't
like the tone. Your first post set the tone. Anything after that was
simply your reflection in a mirror.
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Author: Michael A. TerrellDate: 00:53 05-05-08
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w_tom wrote:
>
> On May 4, 9:14 pm, "Michael A. Terrell"
<mike.terr...@earthlink.net>
> wrote:
> > Bullshit. Transmitters get knocked off the air, and the anteanna
> > grounding systems are damaged from repeated strikes. Onece again, you
> > are blowing smoke.
>
> People who are more than TV repairmen learn from their mistakes and
> correct reasons for that failure. TV repairmen only fix defects -
> never bother to learn how those failures can be avoided. Let's have
> some fun. Let's reply using the same mockery and insult that Michael
> uses. Except this post will be accurate about Michaels intelligence.
If that is true, you will never learn anything. _wacko_tom. BTW, if
you are going to damn others, al least proofread your message before you
hit send. I'm sorry that yo never made it past TV repairman, but I left
that field in the early '70s. That was over 35 years ago, on the day I
was drafted. You are still stuck in the past, quoting things from
organizations that either no longer exist, or have updated their
information. Tell us _wacko_tom, how much of your work is in orbit? Or
used by NASA, NOAA, or the ESA? Tell everyone what you do for a living,
then bore us to death with more of your inane BS, like your claim that
all computers MUST work down to 90 volts because the now deceased CBEMA
said so. Or the fact that you refuse to admit that new version of
standards supersede older ones.
Now, lets examine your intelligence. ... ... ... 0.000. Well, that
didn't take very long. :(
--
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Author: Michael A. TerrellDate: 00:55 05-05-08
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w_tom wrote:
>
> Rush Limbaugh would be proud.
Only of your unending ignorance. That is, if he wasn't afraid that
you were trying to take his job as a fat, drug addicted idiot with a
talk show.
--
http://improve-usenet.org/index.html
Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
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Author: Phil HowardDate: 01:42 05-05-08
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In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
| phil-news-nospam@ipal.net wrote:
|> In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
|> | phil-news-nospam@ipal.net wrote:
|> |> In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
|>
|> |> | You suggest experts in the field "missed a lot of reality" and
"flubbed
|> |> | the experiment".
|> |>
|> |> I propose that as one explanation as to why these guides come up short on
|> |> the explanations.
|> |
|> | Translation - they don't say what you believe. They "missed a lot of
|> | reality" was in response to one of your beliefs that is not found in any
|> | of the rather extensive reading I have done. And another of your beliefs
|> | for which you have no supporting cite.
|>
|> You are likely to never see any citation that attests to what I believe.
|
| Because some of what you believe has nothing to do with the real world.
Which somes are that?
|> | And you are again discounting a guide written by experts, peer reviewed
|> | by experts, published by the IEEE, and aimed at technical people. You
|> | apparently think electrical engineers are idiots. Where you disagree
|> | with the guide you have not cited a source that supports your belief.
|>
|> I've _met_ electrical engineers that are idiots. I've met people in a
|> lot of other fields that are idiots.
|>
|> I don't know if the authors of what you have read are idiots. Maybe they
|> are just not writing as broadly as you think they are.
|
| Of course they are idiots. They are all members of the IEEE. Only idiots
| can join. And only the biggest idiots can write publications for the IEEE.
Your words, not mine.
| Martzloff is not only an IEEE idiot. He worked for the NIST - another
| well known lair of idiots.
Your words, not mine.
| Thank goodness you aren?t a member.
Yeah, right.
|> |> For example, consider the high frequency issue. High frequency energy is
|> |> less common than low frequency energy. Partly this is because the chance
|> |> of a closer lightning strike is less than a more distant one. A strike
|> |> within 100 meters is only 1/8 as like as a strike outside of 100 meters
|> |> but within 300 meters. Some people then feel that they can dismiss high
|> |> frequency energy issues entirely.
|> |
|> | Francois Martzloff was the surge guru at the NIST and has many published
|> | papers on surges and suppression. In one of them he wrote:
|> | "From this first test, we can draw the conclusion (predictable, but too
|> | often not recognized in qualitative discussions of reflections in wiring
|> | systems) that it is not appropriate to apply classical transmission line
|> | concepts to wiring systems if the front of the wave is not shorter than
|> | the travel time of the impulse. For a 1.2/50 us impulse, this means that
|> | the line must be at least 200 m long before one can think in terms of
|> | classical transmission line behavior."
|> | Residential branch circuits aren't 200m.
|> |
|> | Your response: "Then he flubbed the experiment." In another case you
|> | have said Martzloff had a hidden agenda.
|>
|> I addressed this one elsewhere. You seem to have misunderstood him.
|> He did not say that wiring systems do not exhibit transmission line
|> characteristics.
|
| If you had actually read the quote:
| "*it is not appropriate to apply classical transmission line concepts to
| wiring systems*"
| and "*this means that the line must be at least 200 m long before one
| can think in terms of classical transmission line behavior*."
|
| Repeating: "Residential branch circuits aren't 200m."
You are now taking what Martzloff said out of context. He _qualified_
what he said in terms of a statement conditional. Following the part
you just now quoted is "... if the front of the wave is not shorter than
the travel time of the impulse." Then he added "For a 1.2/50 us impulse,
this means that the line must be at least 200 m long before one can think
in terms of classical transmission line behavior."
Hint: what "if" means is that if the conditional is not met, then the
statement does not apply.
Martzloff's statement is actually correct. Your quoting of it is wrong.
I suspect your understanding of it is weak or maybe even wrong. I believe
you are misapplying it. Then when _my_ statement contradicts _your_
incorrect understanding, you somehow think *I* am contradicting him.
His statement is qualified for a specific slow impulse rise time that
corresponds to a lower frequency. He has NOT said (in what you quoted
in earlier posts here) that no surge can ever have a faster rise time.
He has NOT said that you cannot think in terms of transmission line
behaviour for faster rise times, even on shorter wiring/circuits.
I recall there being something he said that I would contradict, but THIS
statement is NOT it.
|> Rather, he points out that one does not need to look
|> at the transmission line characteristics in certain cases.
|
| Like branch circuits under 200 meters long.
See description of your error above.
|> | You claim lightning induced surges have rise times about a thousand
|> | times faster than accepted IEEE standards - which are experimentally
|> | derived.
|>
|> So you are narrowing this statement to only induced surges?
|
| I intended "induced" meaning produced by including the most damaging -
| strikes to utility lines.
The most damaging strikes tend to be ones that are NOT induced. Do you
understand what induction and inductive coupling is?
Lightning does not have to directly strike the wire for there to be a
surge on it. That is induction when there is no direct strike. If the
strike _is_ directly on the wires, that's different (and has the exposure
of substantially more voltage/current).
|> I didn't see where you quoted anything by IEEE or its experts that specify
|> actual rise times of any kind of surge, induced or otherwise.
|
| From the Martzloff quote you didn't read:
| "For a 1.2/50 us impulse". That is 1.2 microseconds rise time.
Oh I read it. You are making presumptions because I did not conclude
the same thing you concluded.
Because he said "For a ...", he is describing an example scenario and
giving the calculated line length where transmission line effects become
significant enough to consider.
| From w_'s favorite engineer source "an 8 microsecond rise time".
|
| Don?t you read anything?
If you had simply said "Don't you read _everything_" then I would have
agreed with you. And that would be because I actually do not read a
lot of, or maybe most of, w_tom posts. I don't even see them all
because he is posting from Google Groups. So I don't know what, or
how much, I missed from him.
And I don't care.
OTOH, I have read the original quotes of Martzloff's statements that you
made, and then I read the subsequent quotes where you have trimmed them
to change the apparent context to support assertions you seem to be making
that Martzloff is not actually supporting.
| The numbers come from an IEEE standard - accepted by everyone but you.
The numbers are example cases. Read what YOU QUOTED ... CAREFULLY!
|> | One of w_'s favorite professional engineer sources says an 8 microsecond
|> | rise time for a lightning induced surge is a "representative pulse",
|> | with most of the spectrum under 100kHz. You don?t get transmission line
|> | effects at 100kHz.
|>
|> I agree that you don't get transmission line effects under 100 kHz for 200m
|> wires ... of any significance to worry about for surge matters.
|>
|> OTOH, you have not shown how even if an 8 microsecond rise time is significant
|> as a representative case, that it can't get shorter than that in severe cases.
|> or even a higher rise voltage (which hasn't even been specified at all here).
|
| I provided 2 direct sources. They follow IEEE standards for rise time.
|
| Still never seen - a cite that supports your opinion.
Why should I even bother? The more you post, and the more you take things
out of context, and the more you misunderstand what you quote, the more I
realize there is no point in making further efforts for you.
| It is Phil?s phantasy physics.
Or Bud's fantasy prose?
--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |
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Author: Phil HowardDate: 01:47 05-05-08
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In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
| phil-news-nospam@ipal.net wrote:
|>
|> Bud is focusing on the low frequency energy and
|> seems to think that is all there us because a lot of documents focus
|> on it because more energy is in the low frequencies. Also, surges
|> that come from a greater distance have the higher frequencies reduced.
|>
|> Bud either does not understand the high frequency energy or just does
|> not believe it can happen. All lightning strikes have it.
|
| Bud has provided 2 sources that directly contradict Phil. (Of course
| they are not as smart as Phil.)
Bud has quoted people like Martzloff out of context.
| Phil has provided no sources to support Phil's Phantasy Physics.
Phil doesn't care.
| (But this is *Phil* - why should he need sources?)
Why should he care?
--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |
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Author: Phil HowardDate: 01:56 05-05-08
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In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
| phil-news-nospam@ipal.net wrote:
|> In alt.engineering.electrical Timothy Daniels <SpamBucket@nospamplease.biz>
wrote:
|>
|> | As always, "w_tom" ignores that the high voltages that short out
|> | "3 miles of sky" will short out the underground power lines which
|> | enter my building and buildings all over America. Anything able to
|> | leap "3 miles of sky" will leap the fraction of an inch between the
|> | power lines and the earthed metal conduit. What is left will be a
|> | much lower voltage spike that can be handled by the average
|> | "plug-in protector".
|>
|> It does not always make the 2nd leap to ground. There is not always a metal
|> conduit available. I've seen such strikes.
|
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| With no service panel suppressor it is well accepted that at about 6kV
| there will be arc-over from bus to enclosure for (US) circuit breaker
| panels. While arcing, the voltage will be hundreds of volts. Since the
| panel/system ground is connected to the earth electrode (US) most of
| surge energy is dumped to earth.
But what is remaining, in a significant surge, is still capable of causing
damage. A surge already has some high frequency energy. That moves on past
the point of arc even before the arc happens. Once the arc is established,
it can then produce its own high frequency effects. Ignoring this leaves
you open to more damage.
| If talking about a plug-in suppressor, Experiments by Martzloff (the
| idiot/member-of-the-IEEE) show surprisingly little energy reaches the
| suppressor. Circuit impedance greatly limits the current, and thus
| energy. Surprisingly, there is more energy at the MOV for lower surge
| currents (on short branch circuits) because the MOV can hold the panel
| voltage below the 6kV breakover voltage. With up to 10kA surges, the max
| energy at the MOV was 34J with most cases below 1.2J.
I've seen surge energy reach an appliance that is significant enough to cause
complete melt through of AWG #8 copper conductors. There was no protection
installed in that particular case.
--
|WARNING: Due to extreme spam, I no longer see any articles originating from |
| Google Groups. If you want your postings to be seen by more readers |
| you will need to find a different place to post on Usenet. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |
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w_tom wrote:
> Same is described by van Deursen and van der Laan when lightning
> caused damage to a nuclear hardened maritime radio station. Did they
> cry, "Woe is me. Nothing can stop lightning damage"? Of course not.
Nono. They cried "w_tom is me. Stop lightning damage I can."
Nick
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Author: TantalustDate: 08:17 05-05-08
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"w_tom" <w_tom1@usa.net> wrote in message
news:6bf6aafc-99ed-47e6-95b3-b98f5a2df8ae@d1g2000hsg.googlegroups.com...
On May 4, 1:24 pm, "Tantalust" <Tantal...@paradise.net> wrote:
> Why do you have this pompous attitude; constantly sermonizing down to
> people
> as if they're your little, personal kindergarten class?
>Ask polite or technical questions =snip=
"Boys and girls....claaaasss........be *polite* to our nice, kind
kindergarten teacher.....". LOLOL
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Author: TantalustDate: 09:24 05-05-08
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"w_tom" <w_tom1@usa.net> wrote
>Yes, plug-in protectors do have limited protective functions.
Look at poor w_tom starting his back-pedalling.
Back-pedalling, back-pedalling, back-pedalling.
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Author: TantalustDate: 09:55 05-05-08
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"G-squared" <stratus46@yahoo.com> wrote in message
news:6d536181-80ae-4dc4-966a-f6a371ac2201@m73g2000hsh.googlegroups.com...
On May 4, 9:24 am, "Tantalust" <Tantal...@paradise.net> wrote:
> "w_tom" <w_t...@usa.net> wrote in message
<snip>
> > We earth a 'whole house' protector AND connect all protectors
short
> > (ie 'less than 10 feet') to single point earth ground so that
> > protection inside all appliances is not overwhelmed. Simple
stuff
> > that so confused trader. trader *assumed* MOVs rather than read
what
> > was posted. trader again demonstrates insufficient technical
> > kowledge justifies his mockery and insult. Mythical MOV inside
> > appliances demonstrate that trader only reads what he wants to
see;
> > not what is posted.
>
> > MOVs inside appliances is another trader myth. Had trader read
what
> > was posted or learned technology, then trader would not invent
> > fictional MOVs inside appliances.
>
> Why do you have this pompous attitude; constantly sermonizing down
to people
> as if they're your little, personal kindergarten class?
>
> You read sometimes like one of those old children's "Golden Books".
>Hey, I LIKED reading Golden Books to my kids. They didn't like W-TOMs
>posts at all.
>GG
I loved Golden Books too... I'm 55 going on 90 and I still read mine
everyday! ;-)
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Author: Tzortzakakis DimitriosDate: 12:21 05-05-08
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On Mon, 5 May 2008 19:21:16 +0300, "Tzortzakakis Dimitrios"
<noone@nospam.void> wrote:
>
>Ο "Tantalust" <Tantalust@paradise.net> έγραψε στο μήνυμα
>news:RPidnaZzhcrV0oXVnZ2dnUVZ_hadnZ2d@comcast.com...
>> "NB" <nobuyout@gmail.com> wrote in message
>> news:b53f2fef-00bd-40d0-9ac1-c69b3bcadf52@x41g2000hsb.googlegroups.com...
>>> Who is W_TOM and why has he appeared in every single thread that has
>>> contained those keywords since 2001???
>>
>> He an obsessive-compulsive disorder victim, apparently driven by some kind
>> of bizarre fetish involving ground rods.
>>
>>
>What kind of ground rods? I prefer steel core, copper clad ones:-) I even
>have the special heavy hammer>
I'm on 2000' of sand, and at the moment, my house earth is the copper
water pipes, but the water corp keep adding plastic bits here and
there, so I don't really trust it. I was going to hammer in a 20'
length of 3/4" copper pipe under a large tree which gets the drain
from my grey water. Probably the best I can do.
I'm not a full bottle on earth loops yet so i don't know about leaving
the water mains connection still connected.
What's the best way to test an earth?
I heard once that a large electric radiator (fire) connected between
active (hot) and the earth will glow as per normal if the earth has
good capacity. Perhaps a current comparison between the earth return
and neutral return would be more informative?
jack
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On Mon, 5 May 2008 09:24:41 -0400, "Tantalust"
<Tantalust@paradise.net> wrote:
>"w_tom" <w_tom1@usa.net> wrote
>
>>Yes, plug-in protectors do have limited protective functions.
>
>Look at poor w_tom starting his back-pedalling.
>Back-pedalling, back-pedalling, back-pedalling.
>
As I understand it, there is not "protection", or "no protection"
That is, it is not black and white, but degrees of protection, as
there are degrees of surge, or spike.
There is absolute protection of whole of house costing many thousands
of dollars, with tinfoil hats thrown in at no extra cost :)
And there is $7 protection against weeny little spikes/surges, and
then there is everything in between at varying prices.
The old saw "you get what you pay for" is generally bullshit IMHO
You get what the bastard will let you get away with IME
jack
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Author: TantalustDate: 14:10 05-05-08
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<spamfree@spam.heaven> wrote in message
news:4egu14daq01hro0aj8c8ugpv3emu5a3h6g@4ax.com...
> On Mon, 5 May 2008 09:24:41 -0400, "Tantalust"
> <Tantalust@paradise.net> wrote:
>
>>"w_tom" <w_tom1@usa.net> wrote
>>
>>>Yes, plug-in protectors do have limited protective functions.
>>
>>Look at poor w_tom starting his back-pedalling.
>>Back-pedalling, back-pedalling, back-pedalling.
>>
>
> As I understand it, there is not "protection", or "no
protection"
> That is, it is not black and white, but degrees of protection, as
> there are degrees of surge, or spike.
>
> There is absolute protection of whole of house costing many thousands
> of dollars, with tinfoil hats thrown in at no extra cost :)
> And there is $7 protection against weeny little spikes/surges, and
> then there is everything in between at varying prices.
>
> The old saw "you get what you pay for" is generally bullshit IMHO
> You get what the bastard will let you get away with IME
>
> jack
Yeah, but search google groups with the terms "plug in protectors".....
returning 33 instances clearly showing that wobbly_tom was bewildered on the
issue and he's back-pedalling now, as we expected.
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Author: Timothy DanielsDate: 14:15 05-05-08
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"Michael A. Terrell" advised:
> Use a combination of protection at the building's main disconnect,
> and individual protection at each critical device.
Does that mean a combination of w_tom's "whole house protection"
and individual "surge protectors" at those "critical devices"?
That's
what I've always felt would be prudent - not a single method of
protection, but a combination.
*TimDaniels*
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Author: Leonard CaillouetDate: 14:24 05-05-08
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"w_tom" <w_tom1@usa.net> wrote in message
news:82da8b44-e386-4911-94c0-99b0671599ee@24g2000hsh.googlegroups.com...
> People who are more than TV repairmen learn from their mistakes and
> correct reasons for that failure. TV repairmen only fix defects -
> never bother to learn how those failures can be avoided. Let's have
> some fun. Let's reply using the same mockery and insult that Michael
> uses. Except this post will be accurate about Michaels intelligence.
I am merely a TV repairman who happens to have quite a bit of education, and
has done much research on the matter. We began installing good basic MOV
based suppression on our clients' systems long ago, using system level units
that protect all incoming lines. We also pay close attention to proper
grounding. What we have found over many years of this practice in one of
the most lightning intense areas of the USA, is that our systems never take
damage. During times of high thunderstorm activity, however, we see several
times the repair volume, and invariably, the user did not use a surge
suppressor. Our clients are happy with the systems that we sell and with
the reliability. There are good reasons to suspect that system level surge
suppressors do work, but grounding cannot be ignored.
As for you w_tom, you have done far more to clutter groups than to provide
any useful information. While your emphasis on grounding is good advice,
much of the rest of your arguments are out of context and misleading.
Michael may be a crochety ass sometimes, but at least he consistently
provides useful information. Stick to preaching the importance of grounding
and give the rest a break.
Leonard
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Author: Mike TomlinsonDate: 14:27 05-05-08
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In article <481f4eb2$0$31762$4c368faf@roadrunner.com>, Timothy Daniels
<SpamBucket@NoSpamPlease.biz> writes
> Does that mean a combination of w_tom's "whole house protection"
>and individual "surge protectors" at those "critical devices"?
That's
>what I've always felt would be prudent - not a single method of
>protection, but a combination.
Yes, but the environment in which the protected dwelling is situated
should also be taken into account. For example, a house in Florida,
with its overhead power lines and frequent thunderstorms, would be a
more likely candidate for a combined approach to surge protection.
On the other hand, installing Florida-levels of protection in a house in
the UK with its infrequent storms, reliable underground power supply and
a decent electrical system with properly earthed sockets, would be a
waste of money.
It is those nuances that w_twat fails to explain when he spouts his one-
cure-for-all-ills religious mantra about every dwelling absolutely
requiring whole-house surge protection. Like another poster to this
thread has said, things are never black and white, but shades of grey.
The sensible approach is to evaluate the risk and install an appropriate
level of protection.
--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf
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Author: bud--Date: 14:30 05-05-08
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phil-news-nospam@ipal.net wrote:
> In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
> | phil-news-nospam@ipal.net wrote:
> |> In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
> |> | phil-news-nospam@ipal.net wrote:
> |> |> In alt.tv.tech.hdtv bud-- <remove.budnews@isp.com> wrote:
>
> |> |> For example, consider the high frequency issue. High frequency energy
is
> |> |> less common than low frequency energy. Partly this is because the
chance
> |> |> of a closer lightning strike is less than a more distant one. A strike
> |> |> within 100 meters is only 1/8 as like as a strike outside of 100 meters
> |> |> but within 300 meters. Some people then feel that they can dismiss
high
> |> |> frequency energy issues entirely.
> |> |
> |> | Francois Martzloff was the surge guru at the NIST and has many published
> |> | papers on surges and suppression. In one of them he wrote:
> |> | "From this first test, we can draw the conclusion (predictable, but
too
> |> | often not recognized in qualitative discussions of reflections in wiring
> |> | systems) that it is not appropriate to apply classical transmission line
> |> | concepts to wiring systems if the front of the wave is not shorter than
> |> | the travel time of the impulse. For a 1.2/50 us impulse, this means that
> |> | the line must be at least 200 m long before one can think in terms of
> |> | classical transmission line behavior."
> |> | Residential branch circuits aren't 200m.
> |> |
> |> | Your response: "Then he flubbed the experiment." In another case
you
> |> | have said Martzloff had a hidden agenda.
> |>
> |> I addressed this one elsewhere. You seem to have misunderstood him.
> |> He did not say that wiring systems do not exhibit transmission line
> |> characteristics.
> |
> | If you had actually read the quote:
> | "*it is not appropriate to apply classical transmission line concepts to
> | wiring systems*"
> | and "*this means that the line must be at least 200 m long before one
> | can think in terms of classical transmission line behavior*."
> |
> | Repeating: "Residential branch circuits aren't 200m."
>
> You are now taking what Martzloff said out of context. He _qualified_
> what he said in terms of a statement conditional. Following the part
> you just now quoted is "... if the front of the wave is not shorter than
> the travel time of the impulse." Then he added "For a 1.2/50 us impulse,
> this means that the line must be at least 200 m long before one can think
> in terms of classical transmission line behavior."
>
> Hint: what "if" means is that if the conditional is not met, then the
> statement does not apply.
>
> Martzloff's statement is actually correct. Your quoting of it is wrong.
> I suspect your understanding of it is weak or maybe even wrong. I believe
> you are misapplying it. Then when _my_ statement contradicts _your_
> incorrect understanding, you somehow think *I* am contradicting him.
>
> His statement is qualified for a specific slow impulse rise time that
> corresponds to a lower frequency. He has NOT said (in what you quoted
> in earlier posts here) that no surge can ever have a faster rise time.
> He has NOT said that you cannot think in terms of transmission line
> behaviour for faster rise times, even on shorter wiring/circuits.
Previously you said Martzloff "flubbed the experiment".
Now you agree with Martzloff that branch circuit must be 200m for
transmission line behavior with 1.2 microsecond rise time.
You say that doesn't apply because surges are faster. Martzloff uses 1.2
us because that is a standard rise time for surges produced by lightning
as defined in IEEE standards.
w_' professional engineer source says 8 micoseconds with most of the
spectrum under 100kHz.
You still have *no sources that support your belief* that risetimes are
far faster.
>
> |> | You claim lightning induced surges have rise times about a thousand
> |> | times faster than accepted IEEE standards - which are experimentally
> |> | derived.
> |>
> |> So you are narrowing this statement to only induced surges?
> |
> | I intended "induced" meaning produced by including the most damaging -
> | strikes to utility lines.
>
> The most damaging strikes tend to be ones that are NOT induced. Do you
> understand what induction and inductive coupling is?
>
> Lightning does not have to directly strike the wire for there to be a
> surge on it. That is induction when there is no direct strike. If the
> strike _is_ directly on the wires, that's different (and has the exposure
> of substantially more voltage/current).
Again you did not read what I wrote (what a surprise):
"I intended 'induced' meaning produced by including the most damaging -
strikes to utility lines."
--
bud--
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Author: bud--Date: 14:35 05-05-08
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w_tom wrote:
>
> Both of Bud's citations - guides for laymen
The IEEE guide is aimed at "electricians, architects, technicians, and
electrical engineers who were not protection specialists."
>
> Bud quotes from Martzloff
> selectively. Meanwhile this conclusion is so fundamental that
> Martzloff makes it the first point in his IEEE paper:
Quotes selectively? How pathetic. w_ forgets to mention that Martzloff
said in the same document:
"Mitigation of the threat can take many forms. One solution. illustrated
in this paper, is the insertion of a properly designed surge reference
equalizer [multiport plug-in surge suppressor]."
In 2001 Martzloff wrote the NIST guide which also says plug-in
suppressors are effective.
> Also are those 'scary pictures of plug-in protectors
And lacking valid technical arguments w_ repeats the lie again.
Still missing - a link to any source that says UL listed plug-in
suppressors made after 1998 are a problem.
Still missing - a source that agrees with w_ that plug-in suppressors
are NOT effective.
Still missing - answers to simple questions:
- Why do the only 2 examples of surge suppression in the IEEE guide use
plug-in suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?
- Why do all but one of w's "responsible manufacturers" make plug-in
suppressors?
- Why does SquareD say in addition to their "whole house" suppressors
"electronic equipment may need additional protection" from plug-in
suppressors.
- Why aren't airplanes crashing daily when they get hit by lightning (or
do they drag an earthing chain)?
For real science read the IEEE and NIST guides. Both say plug-in
suppressors are effective.
--
bud--
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