Re: coax (grounding shield & AC?)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Hi all,

Although I realize that the Blumlein effect has been documented
in certain situations, I have personally been using x-ray cables as
transmission lines from my pig to my primary tank circuit in my
big coils for years and have NEVER experienced it to my know-
ledge. X-ray cable is basically coax cable "on steroids" that is
generally rated at around 75 kVDC. As a matter of fact, I use
the "inside"conductor as the "hot" and the outer braided shielding
as the ground return currently on my Green Monster system.
http://www.teslauniverse.com/members/drieben/
This means that I only have to run one HV line from the pig
to the tank circuit. BTW, I wonder how are the utility power
companies able to run miles of primary lines under ground and
avoid any of the ill Blumlein effects since the lines for this
are obviously shielded and grounded?

David

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Saturday, May 05, 2007 9:57 PM
Subject: Re: coax (grounding shield & AC?)


> Original poster: "M G" <gt4awd@xxxxxxxxx>
>
> Can the Blumlein effect create problems on a smaller power level. For
> instance my 9kv 30ma NST? I would assume that quiet large coax cable
> would be used on a PIG setup, and of course a PIG is capable of
> moving a lot more amperage. Also, does the effect only apply to coax
> being used in Tesla Coil conditions or generally any current passing
> through a coax cable?
> Thanks,
> Matt G.
>
>
> ---------[ Received Mail Content ]----------
>
> Subject : Re: coax (grounding shield & AC?)
>
> Date : Fri, 04 May 2007 16:14:12 -0600
>
>  From : "Tesla list" <tesla@xxxxxxxxxx>
>
> To : tesla@xxxxxxxxxx
>
>
>
> Original poster: "Gerry Reynolds"!
>
>
>
> Hi Matt,
>
>
>
> What Dr R is getting at is the "Blumlein" effect. I have tried to
>
> research this and believe it is a transmission line phenomenum when
>
> improperly terminated. I dont know this definitively but believe its
>
> possible to figure it out if someone would be willing to create the
>
> effect. Presumably one would use a PIG and have a safety gap from
>
> each HV bushing to ground to protect the PIG from damage. The
>
> setting of the safety gap would be larger than usual so one would be
>
> fairly certain that any firing was due to the effect and not to the
>
> the voltages created by the TC. If we can find a volunteer, maybe Dr
>
> R can help that person create the effect based on his
>
> experience. Just an idea :-))
>
>
>
> Gerry R.
>
>
>
>
>
>  >Original poster: "M G"
>
>  >
>
>  >"Don't run it with AC with ! the grounded shield on it."
>
>  >
>
>  >Hi, just wondering why it is not good to use the coax with grounded
>
>  >shield on for AC? I use coax for high voltage wire on my jacobs
>
>  >ladder. I did notice that if the grounding shield was left normal by
>
>  >the high voltage terminals of the NST it would pick up some of the
>
>  >electricity. A small, weak, arc on the other end of the shield would
>
>  >jump to anything conductive, such as your hand. Cutting the
>
>  >shield/coil of wire off about 1" from the terminals stopped the
>
>  >problem though. Is this the reason, or something else?
>
>  >Thanks,
>
>  >Matt G.
>
>
>
>
>
>
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>
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>
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