Re: secondarys for tube coils

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

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

Hi All, Brad

I use the same secondaries for my tube coils as I do for my SG 
systems.  There's no real "standard" to use on either.  With tube coils, 
the base current is usually much higher than SG coils, so if you're running 
a really high powered system, it may be to your advantage to run a thicker 
wire and fewer turns to accommodate this.  One advantage of tube coils over 
SG coils is the much lower top voltage, which translates to less 
turn-to-turn stress on the secondary, and the near-complete risk of 
primary-secondary flashover, unless it's out of tune and the coupling is 
very tight.

  While resonant rise plays a vital role in developing the top voltage, 
it's the application of the RF envelope over time that makes the long 
streamers.  A SG coil literally kicks the crap out of the secondary when 
the gap fires, whereas a tube coil just gives it a good shove.  This is 
visible in the reduced output of a tube coil vs a SG coil with the same 
input power.  That's one reason staccato mode gives long sparks, it helps 
the tube coil to kick the secondary harder, but it's always a 
tradeoff.  With a harder kick, there's less current in the streamers, so 
they're thinner.  With a more continuous push, the top voltage goes down, 
but the streamer current skyrockets.

  Overall, a secondary should work in either application so long as it's 
run within it's limits.

Hope this helps!


At 12:45 PM 3/20/02 -0700, you wrote:
>Original poster: "Brad Huff by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><huffb-at-avalon-dot-net>
>
>Most secondary windings for capacitive discharge systems, that I have seen
>displayed here, are wound with #22 or #24 wire on a 3:1 or 4:1 form, but on
>tube coils people are still using "grandpa's designs". That is small tube
>diameter long forms with #28-#32 magnet wire. Which design is correct for tube
>coils?-Brad.

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Shad (Sundog)
G-2 #1203
"Ever stop to think, and forget to start again?"
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