[BC] Lightning and grounding ... fun for all!

[Bruce Doerle]

Willie,
 
You are right a video is worth an essay.  But I have no intention of writing one.  I was hoping for more comments, but the issue seemed to drop.  The video was meant to stir more discussion.  Lightning protection is an issue that we all need to be concerned about while lightning prevention is not a reality.
 
The video seems to support the claims made by lightning prevention apparatus manufacturers.  Don't let the video deceive you; it is a controled demonstration.  Dr. Mousa discussed this video in his June 27, 2003 email entitled CTS Gimmick by Hitachi/LEC.  It can be read in full on the LightningProtection Yahoo Group.  Dr, Mousa had concluded that the gap factor for the lightning rod and CTS device was effectively different and the breakdown voltage was insufficient for the CTS while sufficient for the Franlin rod.  Moreover, he concluded that the tests have relavance to natural lightning.  I suggest you read his email to understand the technicalities this demonstatrion.
 
In addition, Mr. C. B. Moore of the Langmuir Laboratory for Atmospheric Reseach in a follow-up email (June 28, 2003) added the following comment:
 
"The easy ionization of the air around sharp tips exposed to strong electric fields makes difficult the development of spark discharges from such electrodes - and none are shown in the Hitachi film clip. However, this ionization does not prevent the onset of lightning in thunderclouds, it merely makes the spline ball and similar, sharp-tipped electrodes into "very-reluctant" strike receptors, other objects in the vicinity may receive the stroke because they are better receptors."
 
Open for more comments?
 
Dave, thanks for your input on your emails.   
 
Bruce

>>> WFIFeng at aol.com 05/12/05 7:50 AM >>>

In a message dated 05/11/2005 09:15:40 PM Eastern Daylight Time, 
bdoerle at mail.ucf.edu writes:

> One of the things that came up in June of 2003 was an interesting demo clip 
> from Hitachi.  I was wondering from this group what they thought of this 
> demonstration:
>  
>  http://bellsouthpwp.net/B/r/BroadCastDesign/lightning/Hitachi_prevention_ 
> video_clip.wmv. 
>  
>  Any comments?

That's *exactly* what I was talking about, RE: my post about the Van De Graaf 
generator. I have done this exact same experiment, myself, with exactly the 
same results. Repeatedly. This video clip is perfect... you can very clearly 
see the corona discharge and even hear the hiss, as the "porcupine" is brought 
close to the sphere... and the arcs stop!

A picture is worth 1,000 words, but a video can be worth an essay! ;)

Willie...

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