Re: HV Cables

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Tesla729-at-cs-dot-com 

"Tesla list" <tesla-at-pupman-dot-com> wrote:

 >Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 >
 >----- Original Message -----
 >From: "Tesla list" <tesla-at-pupman-dot-com>
 >To: <tesla-at-pupman-dot-com>
 >Sent: Monday, November 10, 2003 5:04 PM
 >Subject: Re: HV Cables
 >
 >
 > > Original poster: Tesla729-at-cs-dot-com
 > >
 > > In a message dated 11/9/03 12:09:21 PM Pacific Standard Time,
 > > tesla-at-pupman-dot-com writes:
 > > >However, for higher voltage applications, the best high voltage wire out
 > > >there is type RCB wire made by
 >  <snip>
 > > >Dan
 > >
 > >
 > > Hi Dan,
 > > all,
 > >
 > > Yep, sounds like some great stuff but probably most of us can't
 > > afford such exotic cable. Another suitable alternative is the trans-
 > > mission cables that run the HV from the HV ports of x-ray transformers
 > > to the x-ray tube heads. This cable is made just like coax cable that
 > > plugs into the back of your TV from the cable or satellite compa-
 > > ny, only a lot bigger.
 >
 >Not even close...just to discourage folks from using Cable TV coax, which is
 >usually foam dielectric RG-59 or RG-6 coax.  They use foam to reduce the
 >loss, particularly at GHz frequencies (i.e. the output of the LNB on the
 >satellite dish which is around 1 GHz).  Foam dielectric + HV = bad news...
 >
Hi Jim, all,

My mistake. I meant to say that x-ray cables are designed similar
to coax cable in that the "hot" inner conductors are surrounded
by an insulating medium which is then surrounded by a grounded
conductive shield. Yes, the insulation of x-ray cable is heavy
duty red rubber, probably close to 3/8" thick, not anything like
the foam dielectric of coax cable.

 >
 >>That semiconductive layer is the key to quality HV cable.
 >

Agreed and BTW, x-ray cable is quite expensive too, at retail
cost, but can sometimes be found in surplus lots on ebay for
a fraction of the retail cost.

Dr. R, would this type of cable exhibit the "Blumline effect",
seeing that it is wrapped in semiconductor carbon tape be-
tween the rubber insulation and the braided shielding? I,
for one, have NOT noticed the excessive voltage rise using
x-ray cable as the transmission line from the HV from the
power supply to the tank circuit of the coil.

David Rieben