RE: Single-bushing 14.7kV pigs. Thoughts?

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

Original poster: "BrianB" <brianb-at-antelecom-dot-net> 

David/all,

I've had the same experience as Dr. Res when trying to use coax cable as
HV feed-line. The voltage at the PT skyrocketed jumping a 2"horn gap
that just happened to be there. We immediately swapped the PT out with a
Pig (more robust and easier to replace) but experienced the same problem
(this time we purposely placed a horn gap on the Pig so we could monitor
for excessive voltage rise). Changing only the coax out for some 14awg
stranded wire eliminated the excessive voltage and everything functioned
as normal.

Regards,
Brian B.

www.teslacoil-dot-com
www.briananddebbie-dot-com


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, February 10, 2004 11:55 AM
To: tesla-at-pupman-dot-com
Subject: Re: Single-bushing 14.7kV pigs. Thoughts?

Original poster: DRIEBEN-at-midsouth.rr-dot-com

Dr. R,

No, I didn't bother with a safety gap on the pig as pigs are darn-near
bullet proof but I did place a 15 kV lightning arrester across the pig
and it didn't appear to shunt any of the input voltage to ground. I had
used a 12 kV arrester and it would start shunting the input HV to ground
when I cranked the HV up to past 14 or 15 kV. It was pretty easy to tell
when the arrester was starting to clip the HV to the coil as the coil's
output would start to "clip" and fire erratically. I'm reasonably
certain
that both arresters worked properly and the voltage never got high
enough
from the pig to cause the 15 kV arrester to "clip". So it would appear
that there was certainly no "excessive" resonant voltage rise.

David Rieben

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
Date: Tuesday, February 10, 2004 7:00 am
Subject: Re: Single-bushing 14.7kV pigs.  Thoughts?

  > Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
  >
  >
  > Never tried X-ray cable.  Did you have a monitor "safety gap" to
  > detect any
  > resonant rise?
  >
  > Dr. Resonance
  >
  > Resonance Research Corporation
  > E11870 Shadylane Rd.
  > Baraboo   WI   53913
  > >
  > > While this may indeed pose a problem with true coaxial style
  > cable, I know
  > > from experience that this was not a problem with HV x-ray
  > cable. I used
  > about
  > > 18 ft. of x-ray cable for the transmission line between my pig
  > and the
  > coil
  > > and I never experinced the "Blumline effect" with this setup.
  > Of course,
  > > x-ray cable also has a carbon based simiconductor tape wrapped
  > around the
  > > thick rubber insulation between the the rubber insulation and
  > the grounded
  > > outer metal braiding and I'm thinking that this may be the key
  > as to why
  > > the Blumline effect is not noticed in this situation. Just
  > guessing here,
  > > though.
  > >
  > > David Rieben
  > >
  > > ----- Original Message -----
  > > From: Tesla list <tesla-at-pupman-dot-com>
  > > Date: Monday, February 9, 2004 9:01 am
  > > Subject: Re: Single-bushing 14.7kV pigs.  Thoughts?
  > >
  > >  > Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
  > >  >
  > >  >
  > >  >>
  > >  > I also want to share with the group something to never do:
  > On an
  > >  > early pig
  > >  > xmfr we used a coax cable to connect both the hot and ground
  > >  > approx 12 feet
  > >  > over to the coil.  When we fired the coil up the capacitance
  > >  > formed a
  > >  > powerful resonance with the xmfr's inductance.  The result
  > was hot
  > >  > longsparks that fired across the entire large 14.4 kV
  > bushing on
  > >  > the xmfr.  It
  > >  > formed a sort of blumlein and developed over 125 kV across the
  > >  > bushing!
  > >  > Dr. Resonance
  > >
  > >
  > >
  > >
  >
  >
  >