Re: Surge / Ground / Lightning

In alt.tv.tech.hdtv bud-- <remove.budnews@[EMAIL PROTECTED]
> wrote:

| Previously you said Martzloff "flubbed the experiment".

I remember that.  You were telling me about some information he had
obtained from some experiment.


| Now you agree with Martzloff that branch circuit must be 200m for 
| transmission line behavior with 1.2 microsecond rise time.

That's not a result of an experiment.  I'm not so sure the exact distance
is 200m for that exact rise time.  But that is a subjective thing.  We are
likely not that far apart.  It is a matter of degree to how different the
calculations come out when figuring them with transmission line issues and
ignoring those issues.


| 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.

Martzloff did not say that was a defined standard in the statement you
quoted.  He just used it as an example to come up with the 200m figure.
Do you have some other statement from Martzloff or someone else about the
1.2 microsecond rise time?


| w_' professional engineer source says 8 micoseconds with most of the 
| spectrum under 100kHz.

Even with 1 nanosecond rise time, most of the energy will be present in
the spectrum below 100 kHz.  That means nothing when the surge is strong
enough to have energy above some frequency that is relevant to the whole
system involved that can do damage.  That frequency might be 100 Mhz for
some thing, and 1 GHz for other things.  Some surges, mostly from very
close direct strikes, can have damaging energy well above 1 GHz.  It will
depend on how much inductance you have between the surge and the equipment
that needs to be protected.  That's why I suggest that a good protection
scheme will include added inductance on the wiring at a level compatible
with the normal use (more can be added to power than to cable TV).


| You still have *no sources that sup****t your belief* that risetimes are 
| far faster.

I have experience and observation for that.  I need no more.


| 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."

You are saying the most damaging strikes are induced?  Or are you merely
adding the most damaging direct strikes in with the induced surges as a
set of surge cl***** that you want to consider together?

Your wording is so bad in that one sentence that I cannot tell what you
mean.
It is vague and could satisfy more than one meaning.

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