Re HV wire; Safety;
When I built an amp with a separate power supply, heavy, roll around, I felt
uncomfortable with just a polyethelyne or silcone rubber insulation over the
B+. Often, at least in my ham shack, the heavy roll around PS had an
interconnection for the B+ lead which I used RG 213/RG-8 WITH shield intact,
and bonded to both chassis. Sometimes those things found themselves under the
operating bench, where my stockinged feed also were. I just did not like the
idea of, say 3/16" of polyethelyne between me an death, so I kept the shield on
the B+ lead.
I wonder if, say during the history of a hombrew amp with a unshielded RG 8
core, B+ lead, or maybe an auto high tension ignition lead, if the lead was
pinched hard, or compressed, say by a castor rolling over it, or getting hit
between a chassis and a a hard place, while moving, if that can seriously
damage the Polyethelyne or Silicone rubber in the case of auto wire, making it
a hazard if you touched the jacket where the pinch or impact occurred.
Some homebrew supplies used by current enthusiasts might have a history going
back to the 50's... grampa's amp supply, 2 generations old, and may have legacy
damage in the B+ lead.
It would be an interesting experiment to take a hipot tester, and take some
legths of RG-8 or silicone ignition wire, and hit them with, say a hammer,
simulating harsh impacts, and see if the puncture voltage of the jacket was
lowered significantly. Also, if it did, if the amount of wear and tear damage
to the insulation that could cause a danger, would be obvious to routine visual
inspection.
These are the kinds of beasts, I am familiar with, but respect...:
http://www.hamradiomarket.com/articles/Lighten%20Up%20Images/HV-PS1.jpg
http://home.comcast.net/~rbethman/IMAGES/hv-dirty-01.jpg
http://hamradiomarket.com/articles/Titan%20Hybrid%20Images/TPO20.jpg
Speaking of the Joys, and potential dangers or QRO homebrew, Has anyone got a
handle on how often a ham, or family member, goes SK due to HV accidents? 1-2
per year? Less?
has anyone gotten hit with, and survived a 3KV or higher, high capacitance
supply, an experience that they can talk about?
I know, second hand, of one, that put his hands inside the RF deck of his
hombrew amp, after too many beers, and others who were in the room told me:
3KV, BIG BANG! Blue flash! knocked the ham off his chair, and burned his
hands, but not terribly. He was stunned, but OK. Apparently the current went
from his hands, to the close by chassis, and not through his body. LUCKYYYYYY!
All the Best, Pat Barthelow,
AA6EG aa6eg@k6bj.org Skype: sparky599
Jamesburg Moon Bounce Team
http://www.jamesburgdish.org
"The most exciting phrase to hear in Science, the one that heralds
new discoveries, is not "Eureka, I have found it!" but:"That's funny..."
----Isaac Asimov
> Date: Mon, 22 Dec 2008 07:50:19 -0800
> From: gzook@yahoo.com
> To: Amps@contesting.com; walnutcreek@appstate.net
> Subject: Re: [Amps] HV wire
>
> Remove the shield from some solid core RG8/U or RG213/U coax. I have seen
> several commercial (i.e. "sputtering") linears that use this for the HV
> lines. It seems to work very well. Now you do not want to use the foam type.
>
> Glen, K9STH
>
> Website: http://k9sth.com
>
>
> --- On Sat, 12/20/08, walnutcreek@appstate.net <walnutcreek@appstate.net>
> wrote:
>
> I am in need of a section of High voltage wire for a 3500 volt power supply
> I'm rebuilding with new caps and so on. I need 20" to finish it up.
>
>
>
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