RE: Pig setup help.

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

Original poster: "John H. Couture" <couturejh-at-mgte-dot-com> 


JB -

Why are you recommending not to connect the transformer case to the power
line (green wire) ground? It is my understanding that connecting the
transformer case to the power ground (green wire) is to prevent the power
system wiring from creating a hazard. If there is a fault in the transformer
the power system high voltage can cause a high potential from case to
ground. Connecting the transformer case to ground (green wire) can eliminate
this hazard. An electrical fault in the transformer can cause a potential
difference between the power ground and the TC ground. However, check with
the electric company for their transformer grounding rules. They have no
rules for Tesla coils.

John Couture

------------------------



-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, March 12, 2004 11:32 PM
To: tesla-at-pupman-dot-com
Subject: Re: Pig setup help.


Original poster: "J. B. Weazle McCreath" <weazle-at-hurontel.on.ca>


At 06:13 PM 12/03/04 -0700, you 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 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.
  >
<SNIP>
  >
  >Thanks for any help.
  >
  >Steve Vance
  >

Hi Steve, Coilers,

That subject was brought up just the other day.  The principle advantage
is that it allows the inner-most primary turn and the secondary bottom
to be at the same potential.  The hookup is electrically the same for
either the single or two horned pigs, save for the fact that the single
horned pig already has one end of the high voltage winding connected to
its case.

Here's how it's done.  Connect the bottom of the secondary and the inner
turn of the primary to your dedicated T.C. ground.  The tap point on the
primary connects to one end of your tank cap, while the other cap lead is
connected to one of the spark gap terminals.  The other gap terminal goes
to the T.C. ground, which completes the primary circuit.  You can think
of the primary circuit as a triangle, with one side being the primary,
the second side being the tank cap, and the third being the spark gap.

To connect the pig, you connect one high voltage bushing to the common
connection of the tank cap and the spark gap.  The remaining bushing of
a two horned pig or the case of a single horned pig connects to the T.C.
ground.  If it's a two horned pig, also connect that bushing to the case
of the pig.  There's one very important point, namely don't connect the
pig case to the power line (green wire) ground, only to the T.C. ground.
If you have a filter on the low voltage side of the pig, it is OK for
its case or grounding terminal to be connected to the power ground.

I hope this sorts it out, but if you have any questions, fire away.

73, Weazle, VE3EAR/VE3WZL

Details of my "Hyperbaric Gap" and Tesla coil are at:
http://www.hurontel.on.ca/~weazle