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RE: pig in overdrive...



Original poster: "sundog by way of Terry Fritz <twftesla-at-uswest-dot-net>" <sundog-at-timeship-dot-net>

Hi all,

 I'm sorely confused by this.  You said centertapped, which is implying 2
secondaries 180 degrees out of phase at half the total voltage (each leg of
a 12kv NST only puts out 6kv relative to the core(ground).  I can't see how
you'd series it for more voltage, unless you grounded 1 HV output and
floated the core (and case) at 14kv.  Grounding 1 HV leg and floating the
core will essentially make 1 long secondary, but you'd probably have to
fiddle with the primary connections, as the 2 secondaries in each pig would
be out of phase still.  At that point you'd still have the same turn/turn
ratio as you did before (60:1), for 14kv, or essentially a single-ended
tranny.  Then you could run 2 back-to-back like MOTs.   But you'll still
have thi problem of floating the core at HV, and I don't like the idea of my
240v line being that close to a 14kv core (vs a grounded core).

 The insulation in a pig will probably do it, but I can't see how you'd not
have to fiddle with the primary connections.  Did I get this right (it seems
logical to me), or did I hit the nail on the side instead?

											Shad


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, February 27, 2001 1:28 PM
To: tesla-at-pupman-dot-com
Subject: Re: pig in overdrive...


Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<FutureT-at-aol-dot-com>

In a message dated 2/27/01 9:44:10 AM Eastern Standard Time,
tesla-at-pupman-dot-com
writes:

> > You can parallel them, but it's even better to put the outputs in series
>  > if your caps can handle it.
>  >
>  > John Freau
>
>  Hi John...
>
>  series the 2 pigs?  so you are saying that the system can handle almost
>  30KV ?  or
>  am i thinking wrong again about the systems voltage?  Caps are no problem
>  I have 2
>  -at- 50KV .114uF caps in series  e.g. 100KV -at- .057uF approx.
>
>  Scot D

Scot,

I'm not sure what you mean by the system?  The combo of
the series pigs?  You are correct about the ~30kV resulting voltage.
Each pig will still see only ~15kV each with the center point of the
series pig's secondaries grounded.  It's the same as putting two
MOT's in series and grounding the cores.  As far as the rest of
the system handling 30kV, I've recently done tests on my small
research coil (TT-42 type) with 42kV peak on the primary.  Higher
primary voltage is good because it lets you use a more primary
turns for a given bang size (smaller cap value), and improves the
surge impedance and reduces the gap losses.

John Freau