coax cable with AC pole xmfrs

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Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>




A transmission line is essentially a capacitor, ie, plate, 
dielectric, and another plate.  Removing the shield of x-ray cable 
leaves the PE/PP and no second plate, so the normal xmission line 
effect is now missing.  Common example of xmission line would be a 
coaxial cable with its inner conductor and outer braided shield.  RF 
currents travel along a capacitvely equal balanced line.

I used coax cable and noted the entire HV bushing on the 14.4 kV pig 
crawling with capacitive sparks --- that's why I mentioned beware 
using coax at all with pole pigs.  I don't have the pri cap size or 
lengths of cable because this was back in 1967.  I also didn't have 
the equipment back then to do precise measurements.

This was posted only to be a warning to anyone thinking of using coax 
with a pole pig --- don't!  or else you may damage the pig.

Dr. Resonance



> Is the effect one of two I mention below?? or is it a third 
> mechanism?? If it is a transmission line effect, can you explain why 
> removing the shield fixes it and why proper termination 
> doesn't???  If a resonant charging effect, can you descibe the L 
> that the coax capacitance is resonanting with, the resonant 
> frequency, and how this works???   If a third mechanism, I would 
> like to challange you for the benefit of all the readers here to 
> give a quick synopsis of this effect :o)).
>
> Knowledge is everything and sharing it is golden.
> Gerry R.
>
>
>
> Also is it
> > Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>
> >
> > These effects are well documented in Sargent & Dolan's book -- 
> > Power Electronics.  Also covered are both strip line and circular 
> > HV generators. Very novel designs.  It's out of print but I believe 
> > that Bert Pool (Stoneridge Engineering) has some copies for sale.
> >
> > > Anyway, going to the intent of the original post,  I'm trying to 
> > > understand the mechanism of voltage growth when using a shielded 
> > > coax (not because I want to use shielded coaxes, but because I 
> > > want to understand). Is the phenominum transmission line effects 
> > > being underdamped while energy is feeding the line,  is it a 
> > > resonant charging effect (series LC) due to the capacitance of the 
> > > coax, or is it some other mechanism???  Also in the TC context, is 
> > > the blumlein effect the same as the transmission line effect I 
> > > described above or something else???