Re: Pig setup help.

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

Original poster: Bart Anderson <classi6-at-classictesla-dot-com> 

Hi Randy,

As you may have guessed, I don't use a strike ring and it has been a topic 
of dispute over past threads. For your question of a center grounded 
primary: for the purpose a strike ring is used, it doesn't make any 
difference if the center or end is grounded, the strike ring would still be 
employed.

Take care,
Bart

Tesla list wrote:

>Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
>Just a little bit off subject;  if the center of the primary is grounded
>(RF) as described in this thread, is a "Strike Rail" really needed?
>
>Randy
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Monday, March 15, 2004 10:05 AM
>To: tesla-at-pupman-dot-com
>Subject: Re: Pig setup help.
>
>Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
>
>Hi Gerry,
>
>Tesla list wrote:
>
> >Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
> >Hi Bart, John and others,
> >
> >This issue of whether to ground the transformer case (whether it be a
>pig or
> >NST) to mains ground or dedicated RF ground seems to be a reoccuring
> >question that I think has no right or wrong.  I know there are opinions
>on
> >both sides and valid ones.  Each solution has its benefits and problems
>and
> >how one treats this issue depends on how they define their system.  The
> >following are the benefits and problems as I see them:
> >
> >Transformer grounded to mains ground (green wire):
> >
> >Benefit:  transformer fault (like primary to case short or secondary to
>case
> >short) may draw excessive current and blow breaker (note that the
>balast for
> >a PIG or PT may not allow this to happen unless ground fault protection
>is
> >used).  Case is safer, however one still has the bushings that can
>kill.
> >
> >Disadvantage:  A strike to the TC primary (transformer secondary) could
> >flashover to the case and thus the mains ground and kill sensitive
> >components (TV, stereo, etc) also plugged into the mains.
>
>It is possible, but this is true with both configurations, including
>floating configurations. The lowest impedance will feel the brunt of the
>
>hit. Also, consider strike rings tied to rf ground (for all those folks
>who
>use them).  A probability factor comes into play by an increase
>frequency
>of hits (and you will get an increase in primary directed hits if a
>strike
>ring is used, and at times, the primary will get hit as well (especially
>
>for coils with poor field control). I just prefer to minimize the
>possibility's.
>Take care,
>Bart
>
> >Transformer grounded to dedicated earth ground (aka RF ground):
> >
> >Benefit: a strike to TC primary that results in flashover to
>transformer
> >case will directly return to the secondary ground and not contaminate
>mains
> >power.
> >
> >Disadvantage:  transformer fault could result in a HOT case and no
>blowing
> >of the breakers if the dedicated earth ground is not adequate.  If
>adequate,
> >the protection should be just a good as mains ground, but still no
> >guarantees for the balasted pig or PT unless ground fault protection is
> >used.
> >
> >I think one should define danger zones in their system design.  If the
> >transformer is within the danger zone,  grounding to the dedicated
>earth
> >ground is OK.  If outside the danger zone, the transformer should be
> >grounded to mains ground and the bushings protected from accidental
>contact.
> >
> >One persons opinion,
> >Gerry R
>
>
>
>
> > > Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
> > >
> > > Hi Randy,
> > >
> > > Grounding the case to mains ground is for safety. All equipment with
> >direct
> > > feeds should have their case connected to mains ground (this
>includes the
> > > transformer). In the event of a fault, we don't want the case at a
> > > potential that could be lethal. Should there be a fault, the mains
>breaker
> > > will trip and remove all power.
> > >
> > > Take care,
> > > Bart
> > >
> > > Tesla list wrote:
> > >
> > > >Original poster: "Randy & Lori" <rburney6-at-comcast-dot-net>
> > > >Bart,
> > > >
> > > >Why the "mains" ground? I have read:
> > > >2 or 3 RF Grounds
> > > >1 Mains Ground
> > > >1 Mains OK if filter is used
> > > >
> > > >Randy
> > > >
> > > >-----Original Message-----
> > > >From: Tesla list [mailto:tesla-at-pupman-dot-com]
> > > >Sent: Saturday, March 13, 2004 12:44 AM
> > > >To: tesla-at-pupman-dot-com
> > > >Subject: Re: Pig setup help.
> > > >
> > > >Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
> > > >
> > > >Hi Steve,
> > > >
> > > >Tesla list wrote:
> > > >
> > > > >Original poster: "steve" <steve_vance-at-cablelynx-dot-com>
> > > > >I have a question for the list. I have a 10 kva pig I'm running
> > > > >at 5 kva to power my coil my 6.5 inch coil. I was reading the
>archives
> > > > >and came across a post about running one of the hv bushings and
> > > > >the can to earth ground. Can't find enough information to
>convince me
> > > > >that I fully understand how to do this safely. Someone correct me
>if
> > > >I'm wrong
> > > > >on this.... I run one of the hv leads to the can, ground the can
>to
> > > >earth, run
> > > > >the other hv lead to one side of the tank circuit, and the other
>side
> > > >of
> > > > >the tank
> > > > >goes to the rf ground? Or does it need it's own ground rod?
> > > > >
> > > > >Thanks for any help.
> > > > >
> > > > >Steve Vance
> > > >
> > > >You've got it right. The case should be tied to "mains" ground.
>Then,
> > > >240
> > > >to the 2 low voltage bushings.
> > > >
> > > >To bring the inner primary at the same potential (RF ground) as the
> > > >bottom
> > > >of the secondary, tie one side of the hv terminal to RF ground and
>the
> > > >other end to the tank. The hv terminal to RF ground does not need
>it's
> > > >own
> > > >ground. RF ground is where the connection is.
> > > >
> > > >Take care,
> > > >Bart
> > > >
> > > >
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