Re: strike rail mystery. (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

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>
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>---------- 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)
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>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
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>>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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