Re: strike rail mystery. (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: List moderator <mod1@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 03 Jun 2007 01:34:45 -0400
From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: strike rail mystery. (fwd)

I have always wondered what happened in the unused turns of a primary, I 
always just assumed there was little or nothing in there, I guess this 
assumption was very false!  My coils do have several unused turns on the 
primary, which I will probably trim off after I finally settle on a top 
load, but my primary did not arc to anything.  My Strike rail arcs to a 
grounded wire, namely the disconnected lead to the RF ground.  Unless it is 
surface tracking from my primary, to the wire, and then arcing to a floating 
capacitance, the primary is not the culprit, otherwise, I don't see how it 
could be.  The strike rail is not a complete turn, so I don't think it is 
transformer action, but perhaps it is simple magnetic induction of a wire in 
a changing magnetic field?  Any thoughts on this?
Scott Bogard.


>From: "Tesla list" <tesla@xxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: Re: strike rail mystery. (fwd)
>Date: Sat, 2 Jun 2007 16:11:39 -0600 (MDT)
>
>Original poster: List moderator <mod1@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Sat, 02 Jun 2007 14:59:48 -0700
>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: strike rail mystery. (fwd)
>
>Hi DC,
>
>Excellent advice! Your right, if there are several unused turns, there
>is a proximity issue from the strike rail to the nearest winding of
>which may have a multiplier effect due to the number of turns unused
>from the actual resonant tap point. Excellent advice!
>
>Take care,
>Bart
>
>Tesla list wrote:
>
> >Original poster: List moderator <mod1@xxxxxxxxxx>
> >
> >
> >
> >---------- Forwarded message ----------
> >Date: Fri, 1 Jun 2007 23:48:57 -0500
> >From: resonance <resonance@xxxxxxxxxxxx>
> >To: Tesla list <tesla@xxxxxxxxxx>
> >Subject: Re: strike rail mystery. (fwd)
> >
> >
> >
> >
> >In many cases, with classic Tesla coil setups, the experimenter forgets 
>that
> >a "variac" autotransformer effect occurs across the very high Q primary
> >coil.  If you have an extra 3-4 turns hanging on the primary, e.g., your 
>pri
> >tap is in 3-4 turns from the end of the primary coil, very high 
>potentials
> >can exist across the end of the outer turn.
> >
> >This is the principal that Tesla discovered when making his "magnifier"
> >system.  This is, of course, not desireable in a classic coil system 
>where
> >you want the last tap usually within 1 turn of the end.  This is also why
> >I'm a strong advocate of building a "scrap wire" primary circuit before
> >laying on lots of copper tubing, tapping in 4-6 turns from the outer end,
> >and then seeing 8-10 inch long sparks flashing from the last turn to
> >anything grounded, or, worse yet, upwards along your secondary coil.
> >
> >Keep the primaries as "tight" as possible to the required number of turns 
>to
> >prevent autotransformer voltage multiplication due to the very high Q of
> >copper tubing primaries.
> >
> >When Sloan built his 18 turn 1,000,000 Volt, 150 kVA, vacuum tube 
>resonance
> >transformer (I believe it was at Stanford), he applied only 15 kV input 
>at
> >150 kVA from the CW oscillator into a water cooled 2 inch dia. copper 
>tube
> >sec.  He tapped across the first 2-3 turns and developed a tremendous
> >voltage multiplication due to the very high Q effect, i.e., a Tesla
> >"magnifier" effect.
> >
> >This Q multiplier effect is causing your strike rail flashovers.  Trim 
>your
> >pri properly and this problem will go away.
> >
> >These effects along with overly tight coeff. of coupling (k factor) cause
> >many the the "racing spark" problems.
> >
> >Dr. Resonance
> >
> >
> >
> >
> >>To add to DC's statement, when the situation occurred in the beginning
> >>of this thread, the strike ring was arcing across the 3" gap. During
> >>those arc events, the ring was a shorted turn, so power did attempt to
> >>flow and energy was lost. But under normal circumstances, the ring is
> >>not much more than an external capacitance that is felt only slightly by
> >>the secondary. The primary feels the capacitance also but the large tank
> >>cap overwhelms any possible affect.
> >>
> >>Take care,
> >>Bart
> >>
> >>
> >>
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>

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