Re: Freau's efficiency theory=Success!

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

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

In a message dated 6/4/01 10:44:28 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> Hi all,
>  
>  Over the past few months I have built a medium sized Tesla coil
>  based mainly on  John Freau's efficiency theories.
>  http://hometown.aol-dot-com/futuret/page3.html
>   (Very good info John)! 
>  
>  I feel this coil is a  good performer and I wanted to share it's
>  specs with everyone. (Shameless coil gloat)!

Jon,

Your results are better than most of my own !  It shows too that
a small secondary can give excellent results.  It also shows that
a little longer secondary helps to prevent racing sparks.  I used
a 23" winding length, and I used to begin to have racing spark
problems as my spark length went over 60" to 64" or so.  Your
results also suggest that the use of over 1800 turns does not
seem to hurt the performance.  ( I was wondering if performance
might begin to fall off somewhere around that point, esp as sparks
get longer).  It's a good indorsement of the MMC type caps too.

Now you could add some PFC caps to get the VA input down a
little lower, not that it will really make any difference to the
performance.

How many simultaneous streamers emit from the toroid?  Is
the toroid somewhat smooth, or corregated?

Thanks for the report,
John Freau


>  
>  Secondary:
>  Material= Home Depot HDPE drain pipe. (White on the outside,
>  black on the inside).
>  Diameter=4.2"
>  Form length=26"
>  Winding length=24.5"
>  Total # turns=1830, (approx).
>  Wire size=28
>  Inductance=56mH, (measured).
>  Fres, (bare)=219.3kHz, (calculated, my Navy surplus audio signal
>  generator only goes to 200kHz)!
>  Fres, (loaded)=104.4kHz, (measured).
>  Toroid minor dia=5"
>  Toroid major dia=27", (tube center to tube center)
>  Toroid capacitance=32.24pF
>  I also use a 1 7/8" x 6" control toroid that just fits over the
>  secondary.  The lower surface of the control toroid is even with
>  the top turn of the secondary.
>  
>  Primary:
>  21 turns of 3/16" copper tubing spaced 1/4". Tap point is 19.25
>  turns, (measured 145.9uH).
>  Measured Fres at this tap position is 94.7kHz, about 10kHz lower
>  than the secondary Fres. (Coil tuned for maximum spark length)
>  Tank cap=0.0187uF MMC, (Terry's Panasonic caps, 15 caps in each
>  string, 5 parallel strings).
>  Coupling, (K)=0.106
>  
>  Gap:
>  120bps SRSG.
>  
>  Power transformer:
>  Unmodified 12kV 60mA Magnetek/Jefferson NST, (max input 140Vac).
>  VA input=3220, 23A at 140Vac. (No PFC caps).
>  Actual power input=1080Watts (Measured with Wattmeter)
>  Maximum spark=61"
>  
>  
>  Any comments or questions welcomed.
>  
>  Jon
>