Re: NEON DATA 2

To: tesla-at-pupman-dot-com
Subject: Re: NEON DATA 2
From: Ed Harris <harris-at-parkave-dot-net>
Date: Sat, 5 Oct 1996 15:30:31 -0400
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Hi Barry,

Nice neon data. People on the list had long complained that
their neon transformers could not stand up to the brutal
treatment of a Tesla coil primary supply. I think the problem
is really that the neon trans. needs protection from the primary 
tank circuit since the impedance looking into the neon secondary
at the tesla coil operating frequencies is rather low...
Some measurements I did imply that my 60ma 15000V neon
secondry impedance is only a few thousand ohms at around
200kHz. This seems to agree with your lumped secondary
parameters: assume C=400pF roughly from you measuremts.
the Z=1/2piF =1/(6.28*2x10^5)(400x10^-12)=2kOhm ( I ignore
the inductance since it's impedance would be so high).
That means that a significant amount of destructive
current flows into the secondary of the neon when the tank
is oscillating. You'd really have to put in some protective
network between the tank circuit and your neon secondary to
keep it from being damaged.


-Ed Harris 


----------
> From: Tesla List <tesla-at-poodle.pupman-dot-com>
> To: Tesla-list-subscribers-at-poodle.pupman-dot-com
> Subject: NEON DATA 2
> Date: Saturday, November 16, 1996 2:19 AM
> 
> From Benson_Barry%PAX5-at-mr.nawcad.navy.milFri Nov 15 23:11:17 1996
> Date: Fri, 15 Nov 1996 22:53:00 -0400 (EDT)
> From: Benson_Barry%PAX5-at-mr.nawcad.navy.mil
> To: tesla-at-poodle.pupman-dot-com
> Subject: NEON DATA 2
> 
> 
> Ed harris, All,
> Here is more data:
> 
> Correction to previous post.
> I remeasured the 1/2 secondary with a Fluke
> and a megger and got a new value of 2.78 kohm
> for the 1/2 secondary resistance. The previous
> value of 3-5 Megohm is INVALID.
> 
> I remeasured the 1/2 secondary with a pm 6303
> RCL meter made by Phillips and got a value of
> 335 pF for the 1/2 secondary self capacitance.
> With a curve fit in Excel I got a capacitance of
> about 480 pF.  I will therefore show the
> inductance calculation with both values.
> (This meter won't measure the transformer
> inductance or resistance-gives capacitance only??)
> 
> RESONANT    CAPACITANCE  INDUCTANCE      INDUCTANCE
> FREQUENCY   MEASURED     CALCULATED      CALCULATED
>            (335pF) (480pF)
> Hz          pF           Henrys          Henrys
> ____________________________________________________
> 2700       91.5         8.14            0.71
> 500        451          128.91         19.30
> 436        585          144.83         24.74
> 342        1000         162.22         37.34
> 238        1920         198.22         66.54
> 195        2960         202.17         85.84
> 170        3810         211.45         101.80
> 145        5680         200.29         114.96
> 114        8500         220.61         146.55
> 107        9300         229.63         156.91
> ____________________________________________________
> In pspice with R = 2.78 k, L = 200 H, C = 335 pF the resonant
> frequency was found to be around 600 Hz.  I tried to verify this
> but got a very broad "peak" between 430 Hz and 650 Hz with
> the scope connected across the transformer 1/2 secondary
> and the signal generator injecting the signal into the secondary
> via a 1 kohm resistor.
> 
> These things are nebulous to measure at low power levels.
> Barry