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Re: neon vs. potential transformer


From: 	John H. Couture[SMTP:couturejh-at-worldnet.att-dot-net]
Sent: 	Saturday, July 19, 1997 10:44 PM
To: 	Tesla List
Subject: 	Re: neon vs. potential transformer

At 01:26 PM 7/13/97 +0000, you wrote:
>
>From: 	FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
>Sent: 	Saturday, July 12, 1997 3:21 AM
>To: 	tesla-at-pupman-dot-com
>Subject: 	neon vs. potential transformer
>
>  All,
>  
>  Previously, I built a small TC using a 12 kV, 30ma neon trans, which 
>  produced a 42" spark using 740 watts as measured with a wattmeter.
>  Then for comparison purposes, I replaced the neon trans with a
>  potential trans and a suitable ballast, the TC drew about 680 watts
>  and gave the same spark length.  Toroid size is 5" x 20".
>  
>  I also had tried using a 15 kV, 60ma neon trans, which gave a 65" 
>  spark and drew 2600 watts.  Yesterday, I installed the potential
>  trans into the same TC and with 6.7millihenries of ballasting, it 
>  produced a 65" spark and drew 2100 watts.  Toroid size is 6" x 26".
>  
>  An 8 point series rotary sync-gap was used in all the above tests.
>  The potential transformer is rated at 14.4 kV,  1.5kVA. Input power
>  was measured before it entered the main variac.  It is
>  not known exactly how waveform distortion variations might be 
>  affecting the input power measurements.  (Gotta build the "Dave
>  Sharpe" opto-wattmeter).
>  
>  Spark length measurements over 65" length are difficult because
>  the room limits the sparks.  The spark hits the 65" point with a strong
>  "zap" and could undoubtedly go further.  I plan to do more tests and 
>  will try to improve the efficiency.  
> 
>  These results seem to show that when I increased the input power by
>  about 3 times (TCs optimized for the input power--"very" important), 
>  the spark length increased by about 1.73 times.  This follows the direct
>  square law, (more in another post).  
>
>  The lower losses in the potential transformer seem to improve the
>  efficiency of the TC.
>  
>  John Freau
> 
--------------------------------------------

  John F.

  How long were you able to run the 15 KV 60 ma neon at 2600 watts? This is
almost 3 times it's wattage rating. I would expect it to overheat.
  
  You mention efficiency often. How do you calculate this parameter? I am
trying to set up a standard for the efficiency of a Tesla coil. Do you have
any comments?  

  Compared to just a few years ago the average coiler today knows a lot more
about Tesla coils operation than they did in the past. I believe it is time
to set up some standards of testing them so the test conclusions arrived at
make sense.

  Have you checked out this site?

     http://www.capital-dot-net/users/ssilver/tesla.html

  John Couture