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TC enfeeblement (deliberate)


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From:  John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
Sent:  Tuesday, February 17, 1998 11:52 PM
To:  Tesla List
Subject:  Re: TC enfeeblement (deliberate)


  John F. -

  I entered the parameters you show into the JHCTES TC program and found the
following parameters to be within one percent of what you show.
   Pri and sec inductances
   Operating frequency
    Pri turns
  These should be very close as they are parameters of standard equations.
It is obvious your tests measurements were very good because they check with
the calculations.
  
  The pri surge impedance is reduced as you mentioned. In fact the new coil
surge impedance was reduced to 32% of the old coil according to the program.
This is also a standard calculation.

  The old coil has much more inductance than the new coil which would
increase the spark length. However, the old coil with 1500 turns has a lot
more sec wire length than the new coil and this would tend to overload a
coil with small watts input and give  less spark length. In this case the
old coil greater inductance wins out over the longer wire.

  All in all everything checks out except the spark lengths. The program
spark lengths would be less because they are controlled spark lengths.
However, I would not expect them to be only 42% of the random spark lengths. 

  Could you test the two systems with controlled spark lengths? Also, How
did you measure the 640 watts input for both systems? I would expect the
input watts to  change because of the change in pri surge impedance.

  Your tests are very important for developing a complete TC program like
the JHCTES program. Unfortunately very few coilers make these comparison
tests. A comparison test showing all of the changes is the only way to make
a valid test.

  John Couture
  
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At 11:04 PM 2/16/98 -0600, you wrote:
>
>----------
>From:  FutureT-at-aol-dot-com [SMTP:FutureT-at-aol-dot-com]
>Sent:  Monday, February 16, 1998 12:59 PM
>To:  tesla-at-pupman-dot-com
>Subject:  TC enfeeblement (deliberate)
>
>All,
>
>This test shows how certain changes can detract from a coil's
>performance.  We all know that these factors when introduced into
>a Tesla system will degrade its performance, but I thought it might
>be interesting to quantify the effects.
>
>I started with my sync-gap TC that produces 42" sparks using 640
>watts.  Then I replaced both the primary and secondary coils.  No
>other changes were made to the set up.  The new primary has 15
>turns of 8281 coax cable versus the old primary which used 33 turns
>of #12 pvc ins. stranded wire.  We know that the coax cable is
>very lossy, and that the primary surge impedance has been lowered.
>
>The new secondary uses a 7" x 19" plexiglas form wound with about
>530 turns of #24 pvc ins. wire, versus the old secondary which used a 
>6 1/2" x 23" polyethylene form wound with about 1500 turns of #28
>formvar magnet wire.  The inductance of the new secondary is 14mH,
>the old one was 95mH.  
>
>The resonant frequency of the new system is about 300kHz, the old
>one was 100kHz.  
>
>The spark length of the new system is 29", and the sparks look and
>sound weak and feeble.  The old system's 42" sparks were bright
>and bolt-like, teeming with energy.
>
>Both systems use the same power transformer, ballast, .007uF cap,
>5" x 20" toroid, and 8 point series-quenching synchronous 120 BPS
>rotary gap.
>
>I only changed the primary and secondary, but let's consider again
>the parameters that have changed with the new pri. and secondary:
>
>  *Primary surge impedance and inductance is lower
>  *Primary losses are higher due to the coax losses, and the lower
>   surge impedance.  Also gap losses are higher.               
>  *Frequency is higher
>  *Secondary has less inductance
>
>This test does not of course tell us which of the above parameters
>are causing the greatest percentage spark degradation, but it does
>dramatically highlight the need for proper TC design and component
>selection for optimal coil performance. 
>
>I suspect that if the above parameters for both the old and new coils
>are plugged into most TC computer programs, they will fail to predict
>the wide performance variance seen between the two coils.
>
>John Freau
> 
>
>
>