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Re: HV xray cable revisited
Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>
Mike,
I had never even heard of the Blumlein Effect until I
read about it on this list. I think the good Dr. Reso-
nance was the one originally posted info about it to
this list (or at least that's the first message that I recall
reading about it). Anyway, I'm sure it can be a real
issue to deal with under the right conditions, but I per-
sonally have not witnessed any notable effects of this
nature with my x-ray cable power leads and I run 2
cables, each approximate 60' long from the pole pig
to the base of the primary circuit. As I said, I do ground
the outer braids of both to the mains 60 hz ground and the ex-
terior tank of the pig. The only outer braid and semicon-
ductive tape removal that I do is to peel it back 10" or
12" from the hot end of the stripped back central con-
ductors to provide adequate standoff. The thick insulation
between the center core conductors and the semicon-
ductor tape / outer grounded braid can easily handle the
relatively "tame" sub-20 kVAC voltages from the pig.
Also, grounding the outer braid is a matter of safety, IMHO.
As you have already noted, the outer braiding can make
small arcs to grounded objects (or you) if it is energized without
the outer braiding shield being grounded due to capacitance
between the inner core conductor and the braiding. Obvious-
ly, this isn't a safe condition for YOU. Never mind the safety
of your equipment in regards of Blumlein, YOUR safety
must take top priority. You can replace transformers and
capacitors, but you can't replace you! Also, as Terry has
pointed out, you should leave the cable as the way it was
designed to get the designed performance from it.
David Rieben
Original poster: "MIKE HARDY" <MHARDY@xxxxxxxxxx>
Carl Litton was kind enough to respond to this question off-list. He sent me
a pic of 'greenmonster' doing it's spectacular thing. He mentioned you using
xray cable, but failed to tell me you use it with grounded shields in tact.
The way I see it I have 3 choices if I want to use this cable. Do as you do.
Remove the black layer all together, or run it through PVC, or another
suitable insulator. I am very apreciative of all the fascinating discussion
this thread has received.
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, January 06, 2006 11:52 PM
Subject: Re: HV xray cable revisited
Original poster: "MIKE HARDY" <MHARDY@xxxxxxxxxx>
The whole reason I removed the shield in the first place, was all the buzz
about Bluemline effect.
----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, January 06, 2006 11:30 PM
Subject: Re: HV xray cable revisited
> Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi,
>
> What would be ideal... Is to get your hands on this type of stuff...
>
> http://www.okonite.com/Product_Catalog/section2/sheet14.html
>
> Underground, 60Hz rated 15kVac... It is all 150
> amps or greater :o))) :-))))) DigiKey don't sell
> it, but I bet they "throw away" those 200 foot
> extra lengths... Maybe E-bay...
>
> Note all the "semiconducting layer
> stuff"... Don't go messing with that!!! Just
> use the cables just like they were designed to be used...
>
> "105°C continuous operating temperature. 140°C
> emergency rating. 250°C short circuit rating. Excellent corona resistance.
"
>
> This stuff is real "high tech" so don't go
> changing the "system"!!! You can probably dig the sit to find the
details.
>
> http://www.okonite.com/overview.html
>
> But all the corona, HV, leakage, shielding stuff
> has been pretty well figured out over that last
> 100 years, so you should not go changing it on a
> "10 second whim"!!!... The HV cables are darn
> good just as they are and used just as they are
> meant to be used... Avoid the oil and paper solutions from the past :o)))
>
> Cheers,
>
> Terry
>
>
>