Surge / Ground / Lightning
in [Home Built PC]
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From: phil-news-nospam on 4 May 2008 20:27 In alt.engineering.electrical Tony Hwang <dragon40(a)shaw.ca> wrote: | phil-news-nospam(a)ipal.net wrote: | |> In alt.tv.tech.hdtv Tony Hwang <dragon40(a)shaw.ca> wrote: |> | phil-news-nospam(a)ipal.net wrote: |> |> In alt.tv.tech.hdtv Michael A. Terrell <mike.terrell(a)earthlink.net> wrote: |> |> |> |> | Bullshit. Like ALL charges, it simply seeks a complete circuit to |> |> | flow. You have absolutely no grasp of the basic concepts, yet you |> |> | continue to spout your ignorance and lies. |> |> |> |> Not true. |> |> |> |> When you close a switch between a power source and a pair of wires that go |> |> out yonder, the electrical energy does not "know" whether the circuit is |> |> complete or not. If it refused to flow, it would not be able to find out. |> |> It will flow, whether the circuit is complete or not. What happens after |> |> that depends on what is at the other end, which could be an open condition, |> |> a short circuit, or some kind of resistive or reactive load. |> |> |> |> You've claimed to have worked in broadcasting in an engineering role. So |> |> you should understand what happens at the end of an open transmission line. |> |> The electricity flows to get to the open end. Yet it is not a "complete |> |> circuit". |> |> |> | Hmmm, |> | You seem to be confused between current flow(energy) and |> | voltage(poential) Nothing flows in an open circuit. If not we have to |> | rewrite Ohm's law. Show your credential to make a stamement like that. |> | Shameful. |> |> Your knowledge of electricity shows to be a very basic level. You completely |> lack an understanding of how electricity does flow. You have no concept at all |> of transmission lines (and Michael A. Terrell seems to have forgotten his). |> Credentials have nothing to do with whether a statement is correct or not. |> Mine is correct but you don't have sufficient background to even understand it. |> | Plonk!!!!!!!!!!!!! Bye. Nothing missed. Nothing gained. -- |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: bud-- on 4 May 2008 20:47 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. > > | 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. Martzloff is not only an IEEE idiot. He worked for the NIST - another well known lair of idiots. Thank goodness you aren�t a member. > > |> 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." > 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. > > | 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. > > 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. From w_'s favorite engineer source "an 8 microsecond rise time". Don�t you read anything? The numbers come from an IEEE standard - accepted by everyone but you. > > > | 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. It is Phil�s phantasy physics. -- bud--
From: bud-- on 4 May 2008 20:57 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. 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. -- bud--
From: w_tom on 4 May 2008 20:50 On May 4, 3:46 am, Franc Zabkar <fzab...(a)iinternode.on.net> wrote: > OK, thanks. That all makes sense. However, I was thinking of a typical > 2-pin TV, not an earthed computer. Black AC wire surge is now shunted (clamped, diverted) to white wire. Surge now has two paths to obtain earth ground via the TV. One most common path to ground is TV's cable. Why? Cable TV is now properly installed - connected (bonded) typically 'less than 10 feet' to earth ground at the service entrance. If an AC line surge is earthed at that same service entrance using the single point earth ground, then no destructive surge circuit exists through that two wire TV. But the home owner believed myths of plug-in protectors instead of learning why earthing (and 'whole house' protectors) is so important. Whereas surge on cable TV is dissipated in earth, simultaneous surge on AC electric arrives at an adjacent protector, is shunted to white (neutral) AC wire, and now has two destructive paths via that TV to earth ground. Eliminate the plug-in protector to have only one potentially destructive incoming path (increased protection). Or properly earth a 'whole house' protector to have zero potentially destructive paths.
From: w_tom on 4 May 2008 20:59
On May 3, 11:38 pm, Tony Hwang <drago...(a)shaw.ca> wrote: > I experienced a direct lightning strike on a 7 story building. In the > basement there was a large(I mean LARGE) scale data center which I was > in charge of. > The strike clobbered all the data stored in mass storage sub system > requiring 3 days' total system restore. I think when surge is BIG, > nothing can be protected from it. Broadcasting electronics atop the Empire State Building and World Trade Center were struck 25 and 40 times annually without damage. Commercial broadcasters with antennas thousands of feet up also suffer such strikes and cannot suffer damage. Your telco with switching centers in every town; with their $multi-million switching computer connected to overhead wires all over town; must suffer such surges routinely without damage. Mid 1900 research indicates a thunderstorm typically creates maybe 100 surges - and no damage. Likely the outgoing path through that scale was via concrete floor. What was the incoming path? Well what in that circuit was damaged? Or was it only data loss, which means hardware protected itself when too much surge current was permitted inside the building? How many days did your telco require to reprogram that switching center computer after every thunderstorm? They can suffer 100 surges during every thunderstorm and not even suffer data loss - let alone hardware damage? Exactly. Effective protection means every wire in every incoming cable has a short connection to earth via a 'whole house' protector AND separation of up to 50 meters between the protector and electronics. Not used are plug-in protectors. Any protection that would work at the equipment is already inside the equipment. Not acceptable is damage from lightning even data loss. And if damage does occur, telco located and corrected an earthing defect. Another example in Central Florida where Orange County's emergency response system suffered lightning damage. Lightning damage eliminated by fixing the defect - earthing: http://www.psihq.com/AllCopper.htm 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. Their IEEE paper describes how earthing defects (human failures) were fixed. Lightning damage directly traceable to a defect in the earthing system human failure. It is routine to suffer even the most massive surges and no surge damage. Lightning routinely strikes communication facilities on Hoher Peissenberg mountain in southern Germany - without damage. Researchers even mounted electronics equipment to measure the currents of each surge. Did direct lightning strike destroy that electronics and communication equipment? Or course not. It is routine to suffer direct strikes without electronics damage. However the human must first learn what provides that protection - especially proper connections to earth ground. What makes surge protection so challenging? We can test other designs. But we cannot test the surge protection system. Therefore, when damage does occur, the responsible human locates and learns his mistake - often must correct a defective in that earthing system. Numerous professional citations also describe learning from the damage because lightning damage is so easily avoid. A protector is only as effective as its earth ground. As Phil correctly notes: > But it is a matter of how much you want to spend on it. Simple earthing to meet NEC requirements creates significant protection. High reliability facilities may spend even hundreds more to obtain but a little more protection. On average, a destructive surge may occur once every seven years. How much would you spend. $20 for some earthing rods to significantly upgrade protection; or $hundreds to also have protection installed in Central Florida: http://members.aol.com/gfretwell/ufer.jpg How much was that data worth? A question asked of others since Tony Hwang routinely denies this stuff. He suffered massive station damage. Then he declared nothing can protect from lightning even though his industry peers says completely otherwise. |