Using Neon Discharges for Resonant Frequency Coil Testings/ perplexing phase angle problem.

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

Original poster: "harvey norris by way of Terry Fritz <twftesla-at-qwest-dot-net>" <harvich-at-yahoo-dot-com>

For those not wishing to make the expensive purchase
of a signal generator, to accompany use of the scope,
I have found that the solid state NST's can be used
for a similar purpose.  Since they already put out a
sort of "high freq" in continuous wave mode, one can
take a neon in series with the coil on transformer
output, and then scope out the coil to find the ring
captured on the harmonic of the AC cycle.

This is not the only method of using neon discharges
to make resonant frequency scopings. If one has a high
voltage source, (possibly a small TC with variac
regulation to cause  just enough voltage to operate
for one ended neon discharges to a polar capacity
metallic ending), the bulb  and its ending metallic
area can be placed inside the secondary, and then that
secondary can be scoped.  Here are some jpegs, showing
how both methods delivered similar results, and how
they correspond to the mathemathics of resonant
frequency determination.

For the second method making for neon polar capacity
discharge inside a tesla secondary I employed
alternator inputs to accomplish this, so I cant say
for sure whether a small tesla coil could be used,
since its primary arc gap might make a lot of noise on
the scoped signal, but I imagine a tube coil might
work, or any source of  high voltage CW, ie continuous
wave operation. No arc gap was employed here, just
sufficient source frequency high voltage;

Neon Polar Capacity Bulb to TC secondary interior
volume for scope test
http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00266.jpg
And also the actual scoping from that test;
TC Secondary scoping by neon polar capacity/
(alternator) air core transfomer method/ 0.5
volts/div; 5 us/div
http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00263.jpg
The larger amplitude signal clearly matches the
mutitracing signal showing a ringdown of 5 1/2 cycles
for the sweep sweep time of 50 us, or an individual
cycle time of 9.09 us or by taking the reciprocal to
find the frequency, we arrive at 110,000 hz.

Now let us compare this signal to that made by soild
state NST,  scoped coil made in series with bulb
method;

When the secondary coil is added in
series, and the voltage meter changed to record only
the voltage
across the argon bulb, it then drops to 515 volts
across the bulb,
with an additional 140 volts across the series coil,
and a scoping
across the coil in series then shows 18 cycles for a 1
ms sweep
across the screen, or actually 18,000 hz, instead of
the suspected
20,000 given by the manufacturer of the NST in its
spec.s. This has
been showed in the jpeg
Solid State 20 khz NST; scoping across 20.5 mh coil in
series with
argon bulb: 0.1ms/div: 50 volt/div. 18 cycles /sweep
<http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00302.jpg>
Now apparently what happens is that because this coil
is in series
with the bulb discharge, the natural resonant
frequency of that coil
in series adds "ringing" to the AC cycle, so that
higher harmonics
then appear on the AC cycle. As will be seen this does
not occur when
we do just a scoping across the bulb itself, which has
now been
enabled with the smaller 4 inch neon. That scoping
became possible
because it took far less voltage to ignite that bulb
as will be
explained. But first let us see how this ringing
corresponds to an
actual resonant frequency scoping of the coil, and to
cite some
mathematics and observations about how this all
correlates.
First we can turn up the sweep rate to show this
ringing;

Now let us expand this sweep rate 5 times to see the
ripple involved,
that ripple is the influence of the natural resonant
frequency of the
coil taking energy from the cycle and giving it back
again;

Solid State 20 khz NST; scoping across 20.5 mh coil
with bulb in
series; 20us/div; 50 volts/div
<http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00308.jpg>
Now we can expand this sweep rate one more time to get
a more exact
time of cycle;
Solid State 20 khz NST; scoping across 20.5 mh coil
with bulb in
series; 10us/div; 50 volts/div
<http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00309.jpg>
Next we can go up two more sweep rates to 2us/div.
Solid State 20 khz NST; scoping across 20.5 mh coil
with bulb in
series; 2us/div; 50 volts/div
<http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00312.jpg>
These signals appear to resemble a one sided polarity
vibration,
obviously because the triggered sweeping may be
accentuating a
vibration on one side of the previously shown higher
harmonics on the
AC waveform. Counting the divisions across the second
cycle of the
higher amplitude signal, this appears to be about 8.4
to 8.8 us cycle
time, or vibrations between 119 khz and 113 khz.
But on the former sweep rate of 10 us/div, there
appears to be a ~ 6
cycle harmonic riding on a single cycle of the 18,000
hz, or 6 * 18
khz = 108 khz.
One of the problems with this kind of testing is that
we arrive at a half wavelength value instead of a
quarter; from R Hull commentary;
<http://groups.yahoo-dot-com/group/teslafy/message/478>
"For those not well acquainted with Tesla coil design
and operation,
Hull begins by pointing out that, fundamentally,
grounding the base
end of a vertical coil forces a node at that end, and
the coil
resonates at its natural 1/4-wavelength frequency. A
"good" ground
connection is a must. If, however, the coil is
ungrounded, and
typically placed in an elevated, horizontal position,
the coil then
self-resonates at its natural 1/2-wavelength frequency
with a node
forced at the center. "
Also,
"If we place a quantity of electrical energy into the
coil and do it
quickly enough, the coil will ring at its natural
resonant frequency,
much like a bell. Voltage nodes and peaks will appear
along the coil.
If the coil is floating in free space, it will tend to
oscillate at
its natural 1/2-wavelength resonant frequency, and
each end of the
coil will exhibit a voltage peak while a voltage nodal
point will
exist in the exact center of the coil. If, however, we
ground the
base of the coil, this is a forced nodal point and the
coil will
oscillate at its natural 1/4-wave resonant frequency.
"
Now for the maths invovled;
<<http://www.pupman-dot-com/listarchives/1996/june/msg00227.html>>


"Getting on with the comparison, I used 3
500 ft spools(of 14 gauge wire) for a total of 1500 ft
which yeilds a
quarter wavelength of .28 mile. Thus one cycle occurs
in 6.1 Us in which the reciprocal of this is around
163,600 cycles per second. Applying the above given
information in meters to the above formula where the
fifth root of 1.52 is given as 1.086 yeilds around
222,600 hz in my calculations.
A description of (above tesla list archived) Harris
formula;
"If you are just interested in computing self-resonant
frequencies there is another method which I have found
useful and generally accurate to about 10% for all
coil sizes - space wound or not. Its limitation is
that it probably shouldn't be used for aspect ratios
(Height/Diameter)<1 due to the assumptions of the
original derivation. Freq=29.85 *{the fifth root of
H/D}/[N*D] where F= self resonant frequency in Mhz of
an 'isolated' coil H= coil height in meters D= coil
diameter in meters N= total number of turns Applying
the formula to 31 inches,[or .79 meters] of 20 inch
diameter, or [.52 meter] Sonotube only yeilds a H/D of
1.52, not a good ratio for a tesla secondary, however
two were built for a possible future bipolar
application. The other unusual parameter in applying
this formula to my first coil attempt some years ago
was that I used #14 gauge wire for the secondary, only
yeilding 9 turns/inch or a low 280 for the N figure."

So to conclude here the formula predicts ~ 222,000 hz
for a
quarterwavelength value, but the testing method is
yeilding a
halfwavelength value, which would be twice the time
for a resonant
cycle, yeilding half of that frequency, or
approximately in agreement
at ~ 111,000 hz, where the actual alternator neon test
with scope
delivered a frequency of ~110,000 hz.
I have found that with using the higher input
frequencies available with alternator resonant voltage
rise, the signals can be made to look much cleaner,
and that these solid state transformers can also be
operated at 480 hz to show a cleaner ring. They can
also be conveniently tested with typical multiturn
coils, to show that internal capacity between windings
can provide for a SIGNIFICANT reduction of resonant
frequency, something not much studied by the theorists
out there. Here a 500 ft length coil of multiturn
windings obtained as a typical hardware store bought
coil is tested for ring, and it gives only a slightly
higher value than the 1500 ft solenoidal version of
the same thing on 14 gauge wire;
Background Scoping of 11 mh coil in series with 17,500
hz neon
current/ 20 Khz NST/ 185 volt 480 hz resonant
alternator primary/ 20
volts/div; 20 us /div
<http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00332.jpg>

200 volts are recorded across bulb, with a 45.7 ma
input from 185.3
volts from 480 hz resonant alternator inputs. When
this same thing is
done at 60 hz, the voltage across the bulb appears
near 290 volts,
but it does not do this with alternator inputs.

Now note the more sporiadic impulse when the same
thing is done with a 60 hz  primary;
Scoping of 11 mh coil in series with 17,500 hz neon
current/ 20 Khz
NST -at- 114 volt 60 hz variac/ 20 volts/div; 20 us/div
<http://groups.yahoo-dot-com/group/teslafy/files/ATC/Dsc00338.jpg>

Another possible benefit of these transformers is that
gas bulbs also seem to be easier ignited at the higher
input frequency, where here a 4 inch neon will ignite
near the lower 200 volt range, meaning one can also
scope out actual gas discharges with these
transformers, which before may have been prohibitive
or possibly exceeding the voltage limits of most
scopes.  There are also some strange things that
happen when recording voltages with anaolgue voltage
meters. The higher input frequency will cause the
internal impedance of the meter to become more
significant compared to the impedance of what is being
measured. A 200 volt reading becomes a 92.5 volt
reading when the lower scale is changed from 1000 volt
full deflection to the next lower range of 250 volt
full scale deflection, indicating that perhaps each
scale reading must have correspondingly higher
internal impedances.
More extensive commentaries with  this latest solid
state NST research  is covered in the last two teslafy
postings
8 jpegs of latest 18,000 khz NST work.
http://groups.yahoo-dot-com/group/teslafy/message/516
(this covers the alternator side of things better in
explanations)
No Frequency Multiplication Noted by Driving Solid
State NST at 480 hz Alternator inputs
http://groups.yahoo-dot-com/group/teslafy/message/517
Finally to conclude here, I am hoping some "experts"
can supply an answer to the following phase angle
problem, which to me seems a bit perplexing;
"The problem breifly reformulated is this. 590 volts
appears across a
bulb, at a frequency of 18,000 hz. We do not know the
amperage
consumption or the phase angle of that impedance load.
Then a known
purely inductive reactance of 2317 ohms made at 18,000
hz is added
in series, whereby we then speculate that the unknown
amperage
consumption on the secondary has decreased to 3/4 of
its former
level, indicating the addition of 4/3 more impedance
on the
secondary, with a new unknown phase angle made by that
addition in
series for all practical purposes, a purely inductive
reactance.
These facts are predicted from observing the primary
amperage
consumption differences of 120 ma for bulb alone, and
90 ma for coil
in series with bulb on secondary, on the solid state
18 khz
transformer secondary, with primary amperage
differences being known,
but not the secondaries. Now the voltage across the
bulb decreases
to 7/8 of its former value, and not the lesser 3/4 of
its former
value, which would occur if both impedances were
predominantly
inductive. The new voltage distribution from the
former 590 volts
total now becomes 515 across the bulb and 140 volts
across the pure
inductive reactance of the coil. What, if any phase
angle
considerations can be gleaned from the above
information? A phase
angle of 45 degrees would mean that both the X(L)
inductive
reactance, and R resistance would be equal, and for
conventional
frequency determinations at 60 hz would actually
involve a fairly
huge inductance. But here because the frequency is
already so high we
can speculate that the inductive reactance from the
gas discharge
itself would be high, as that current going through
the bulb does
also produce a magnetic field that causes a higher
inductive
reactance to be present as a component of its
resultant phase angle."
(Finally to try and conclude again; considering the
low cost of these items, and the comparative costs of
a signal generator, if they can be used to find
harmonics of rings for coils by using them in series
with bulbs as a continuous wave generator, they should
have some practicality for the TC enthusiasts.  In
fact I have ordered 3 of these to do some
experimentation with a 3 phase, alternator inputed
"continuous wave" TC idea, where I will increase the
ring factor by next employing capacities in addition
to inductances in conjunction with those outputs. I
consider this a "theoretical bonanza" because for the
compactness involved here, I should be able to
investigate  possible self reaction forces betwen 90
degree timed electric and magnetic fields found in
source frequency resonances.  This will take the form
of a wye based air capacity, with windings arranged so
that the magnetic field from one phase can
orthogonally react with the electric field from
another phase. Perhaps this is a little off topic for
tesla list, so I will adhere to the principle of not
promoting something, without first testing it. For
anyone wishing to purchase these low cost items, here
is a Ebay URL,
http://cgi.ebay-dot-com/ws/eBayISAPI.dll?ViewItem&item=1786345993
and Thank you Terry Fritz  for informing me off list
where these  soild state NST's could be obtained!)
Sincerely HDN


=====
Tesla Research Group; Pioneering the Applications of Interphasal Resonances 
http://groups.yahoo-dot-com/group/teslafy/

_