Re: Surge / Ground / Lightning

phil-news-nospam@[EMAIL PROTECTED]
 wrote:
> In alt.tv.tech.hdtv bud-- <remove.budnews@[EMAIL PROTECTED]
> wrote:
> | phil-news-nospam@[EMAIL PROTECTED]
 wrote:
> |> In alt.tv.tech.hdtv bud-- <remove.budnews@[EMAIL PROTECTED]
> wrote:
> |> | phil-news-nospam@[EMAIL PROTECTED]
 wrote:
> |> |> In alt.tv.tech.hdtv bud-- <remove.budnews@[EMAIL PROTECTED]
> 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 sup****t 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--