RE: Freau's efficiency theory=Success!

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-worldnet.att-dot-net>


Jon -

I ran your TC numbers with the JHCTES programs and your numbers and the
programs were in close agreement except for the coupling. You show a K =
.106 and the program shows a k = .17 coupling.

In one of my books I show how the coupling can be easily tested using the
standard equation

      K = sqrt(1-(Fo/Fs)^2)

      Fo = Frequency with secondary open
      Fs = Frequency with secondary shorted

I would be interested in what you find if you make this test.

The JHCTES also shows an overall efficiency of 40%.

     Eff = output/input = 432/1080/12 = 85 watts per foot

The old standard is 500 watts per foot so your coil is doing much better.
The 500 watts actually doesn't make much sense because it is obvious that
modern coils can do much better.

John Couture

-----------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Monday, June 04, 2001 7:43 PM
To: tesla-at-pupman-dot-com
Subject: Freau's efficiency theory=Success!


Original poster: "Jon Rosenstiel by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jonr-at-pacbell-dot-net>

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)!

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