Surge / Ground / Lightning
in [Home Built PC]
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From: w_tom on 5 May 2008 00:17 On May 4, 11:35 am, Mike Tomlinson <m...(a)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.
From: w_tom on 5 May 2008 00:37 On May 4, 1:24 pm, "Tantalust" <Tantal...(a)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, 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 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.
From: phil-news-nospam on 5 May 2008 01:42 In alt.tv.tech.hdtv bud-- <remove.budnews(a)isp.com> wrote: | phil-news-nospam(a)ipal.net wrote: |> In alt.tv.tech.hdtv bud-- <remove.budnews(a)isp.com> wrote: |> | phil-news-nospam(a)ipal.net wrote: |> |> In alt.tv.tech.hdtv bud-- <remove.budnews(a)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) |
From: phil-news-nospam on 5 May 2008 01:47 In alt.tv.tech.hdtv bud-- <remove.budnews(a)isp.com> wrote: | phil-news-nospam(a)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) |
From: phil-news-nospam on 5 May 2008 01:56
In alt.tv.tech.hdtv bud-- <remove.budnews(a)isp.com> wrote: | phil-news-nospam(a)ipal.net wrote: |> In alt.engineering.electrical Timothy Daniels <SpamBucket(a)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. | | | 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) | |