Re: Lightning protection


"w_tom" <w_tom1@xxxxxxxxxxx> wrote in message
news:42CD80FC.B52A188A@xxxxxxxxxxxxxx
> Point one. Deny citations from industry professionals by
> refusing to read them. An ostrich does that; not an informed
> human. Cited are numerous technical papers and other
> technical facts on lightning - literally a full days worth of
> reading. Instead TimPerry pretends those citations did not
> exist in:
> http://makeashorterlink.com/?X61C23DCA
>

one has no way of knowing who is an "industry professional" and who is a
yoyo.


> A DC pulse is an oxymoron. As confusing as another
> ridiculous term: DC triangle wave. Either it is a pulse
> affected by reactance (inductors and capacitors), or it is
> only DC that completely ignores reactance. One cannot have
> it both ways. Either it is DC that ignores reactance, or it
> is a pulse that makes reactance relevant. Which is it? If
> lightning is DC, then inductance, capacitance, and impedance
> is not discussed. Why do industry professionals discuss these
> repeatedly? Because lightning is not DC.
>
> Pulses are transient responses - taught in 1st year
> engineering - an introduction to AC characteristics. AC
> analysis makes wire inductance and capacitance significant.
> DC analysis ignores inductance and capacitance. To understand
> how lightning works - as cited in
> http://makeashorterlink.com/?X61C23DCA - one cannot pretend
> lightning is DC. A lightning impulse is an AC or transient
> event. Lightning is a composition of many frequencies. Show
> me a DC wave that has frequency components? You cannot. That
> is the oxymoron of DC pulse. A 'pulse' has AC components.
> 'DC' has no AC components. Oxymoron.
>
> Equally confusing is to say "DC triangle wave"

nothing confusing about it to me. if a waveform lies above reference ground
it becomes fluctuating DC regardless of its shape, frequency, pulse
repetition rate. id just call it a triangle wave or sawtooth or whatever.
the DC part is usully understood.

you see the electrons are all moving in one direction through a conductor...
that's what Direct Current is. when the little suckers stop and reverse
direction on a regular basis then voila! we get Alternating Current.




.. DC pulse or
> DC triangle wave - both are oxymorons. Both contain numerous
> frequency components. Therefore a 'DC pulse' cannot be
> analyzed using DC analysis. Lightning requires AC analysis.
> Lightning is not a DC event.
>

shure is. next thing you know you'll be telling me that a flashlight is AC
because when you turn it on it has a fast rise time, a finite duration, and
a falling edge when you turn it off.... one big square wave.... plus a few
harmonics... and a tiny bit of RF.



> Point two. TimPerry believes a batting cage set in concrete
> is not conductive.

yep that's what i believe. assuming a typical chain link fence type
arangement. granted that any insulator has a breakdown point. i beleive that
a barefoot boy leaning aginst a batting cage in a thunderstorm is a bad
thing. even a boy in wet sneakers.

now should said cage be grounded with standard 8 foot rods at each corner
and possibly at intermediate points i might feel differently. its just that
i have never seen one treated in such a way. (remember we are talking little
league here). even in this case i wouldnt be comfortable. a direct hit by
approx 20,000 amps is not something i would care to experiance given the
choice.
in any event, i personally prefer to be at home or on a nice building during
lightning storms. after the storm has passed i then go to various locations
as needed and reset breakers, make repairs, or go to backup systems.



TimPerry should first read those
> discussions he refused to learn from in:
> http://makeashorterlink.com/?X61C23DCA

sorry, if i cite a reference it will be to an accredited text, validated
research paper, or at least a website from a reasonably reputable
organization or agency.



> A most superior earth ground is an Ufer ground. Why? The
> earthing is through concrete. Had TimPerry first learned what
> industry professionals teach, then he would have known the
> batting cage mounted in concrete makes a best earthing ground
> - exactly like Ufer grounds. But then TimPerry also promotes
> an oxymoron called 'DC pulse'. Somehow he knows without first
> learning the facts. If only he had first read those citations
> and first learned about Ufer grounding. Then he would not
> have posted, "i dont think so." One should first learn before
> knowing something.
>
> The energy of lightning is AC electricity.
>
> TimPerry wrote:
> > citing a newsgroup discussion is not a valid reference.
> >
> > elaborate (and probably inaccurate) discussion as to the exact
> > nature of lightning will not be of benefit to the original poster.
> >
> > a DC pulse is still a DC pulse no amount of wishful thinking will
> > turn it in to AC (granted that there are some aspects that generate
> > RF and perhaps some other characteristics that may be able to be
> > handled by AC analysis)
> >
> > looking at a few of toms 16,900 archived posts i see he also
> > claims that a ground rod in rock will make a perfectly good
> > ground. from that it follows that a batting cage set in concrete
> > is adiquitly grounded. i dont think so.




.

Relevant Pages

  • Re: Lightning protection
    ... Instead TimPerry pretends those citations did not ... A DC pulse is an oxymoron. ... lightning is DC, then inductance, capacitance, and impedance ...
    (sci.electronics.repair)
  • Re: Bonding help
    ... also installed for lightning protection - from a direct strike. ... AWG is sufficient to earth a direct lightning strike and still remain ... temperature will increase until the melting temperature of 1065 C ... Onderdonk's equation takes into account the time course of the pulse, and is probably more relevant here. ...
    (rec.radio.amateur.antenna)
  • Re: Lightning protection
    ... Pulses are sums of numerous frequencies - numerous sine ... A pulse is not just a pulse. ... That is also true of lightning. ... I never said the earthing wire for a lightning rod must not ...
    (sci.electronics.repair)
  • Re: Lightning protection
    ... sine waves go forever in time. ... exist only during the period of that pulse. ... Wavelet as a better description would be nice. ... even know how to begin to describe a lightning pulse in terms ...
    (sci.electronics.repair)