Re: [TCML] Where to mount the HV Transformer? Under the coil orotherwise ?

["David Rieben" <drieben@xxxxxxxxxxx>]

Hi Jeremy,

You would need the heavy duty coax cable, like RG-58?.
That cheap junk that comes to the back of your cable TV
box uses foam insulation and would promptly fail under the
high voltage stress of Tesla coil transmission line service. I
personally like to use surplus x-ray cable for this purpose.
It is basically a coax cable on steroids and us usually rated
at around 75 kVDC standoff between the inner conductor(s)
and the outer braid. It is typically around 3/4" in diameter
and I have had very good success using this as a transmis-
sion line for the HV from my pole pig to my Green Monster
Tesla coil. http://www.dawntreader.net/hvgroup/david/gm.html

David Rieben



----- Original Message ----- 
From: "Jeremy Scott" <supertux1@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Wednesday, June 25, 2008 12:36 AM
Subject: Re: [TCML] Where to mount the HV Transformer? Under the coil 
orotherwise ?


> I read the coax idea off of this site:
>
> http://www.pupman.com/safety.htm
>
> Somewhere in there it says this:
>
> "The transmission line between your high voltage transformer and your 
> tesla coil is another potential source of electrocution. This should be 
> constructed using neon sign wiring (rated to 40 kV) or thick coaxial cable 
> like RG-8A/U or RG-11A/U. If using coaxial cable, use the inner conductor 
> for the high voltage, and strip back the outer braid about 6-12 inches 
> from each end. Connect one end of the braid to your RF ground. Leave the 
> other end unconnected so it does not form a current loop. Some coilers 
> also place their high voltage cables inside a plastic conduit, which is 
> laid on the floor. This also protects the cable somewhat from strikes."
>
> I was just wondering if anyone has any experience doing it that way.
> This is basically the 50 and 75 ohm impedance cable that you can get 
> anywhere. They have a thick PTFE insulation between the core conductor and 
> the braid which I think would be ideal for isolation. The braid being a 
> nice additional safety feature.
>
> On the other hand... just don't know.
>
> It would be interesting to see just how much voltage it takes to pop one 
> of those cables.
>
>
> --- On Tue, 6/24/08, MIKE BAILEY <m.bailey@xxxxxxxxxx> wrote:
>
> > From: MIKE BAILEY <m.bailey@xxxxxxxxxx>
> > Subject: [TCML] Where to mount the HV Transformer? Under the coil or 
> > otherwise ?
> > To: tesla@xxxxxxxxxx
> > Date: Tuesday, June 24, 2008, 4:42 PM
> > I have my transformers mounted in my control cabinet and run
> > coax cable out to my RSG mounted under the coil , seems to
> > work good no problems so far. I would not connect the
> > braided part of the coax to rf ground , if there are any
> > weak areas in the insulation between the center conductor
> > and the braid or any microscopic holes it will eventually
> > fail and you will have a short to ground and the cable
> > could catch fire. I had a situation where I think there was
> > a break in the center conductor and arcing occured which led
> > to the white cable i was using turning black and started
> > smoking . what I do is just strip the outer layer of
> > plastic and expose the braid and connect it all together
> > with the center conductor and leave lots of space between
> > the 2 cables running out to the coil.
> >
> >   Mike
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
>
>
>
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