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In alt.tv.tech.hdtv bud-- wrote:
| wrote:
| In alt.tv.tech.hdtv bud-- wrote:
| | wrote:
| | In alt.tv.tech.hdtv bud-- 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) |