Re: SS Neon power transformer operation

["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>


--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "David Speck by way of Terry Fritz
 > <twftesla-at-qwest-dot-net>" <dave-at-davidspeckmd-dot-org>
 >
 > Group:
 >
 > Has anyone had experience with the 220V 50 Hz input,
 > 15 kV, 20 kHz 20 mA
 > output solid state neon supplies being offered on
 > eBay for $9.99 each?
I was interested in seeing how these solid state
transformers might work with driving L and C
combinations that would be resonant to the stated
20,000 hz output. They do not work for that purpose as
far as I have seen. They are made to drive gas bulbs
only. It might be possible to put L and C quantities
in series with a gas bulb however, as I have done this
with inductors, but not yet done work with placing
actual L and C resonant combinations.  When placing
just an inductor across the secondary, the transformer
acts in a highly non linear primary amperage
consumption. This was seen in driving it with a 150
volt variac. At around 100 volts it suddenly starts
consuming about 20 ma.

Near the 100 volt range the transformer can be heard
to buzz, at around 110 volts ~ 42 ma is obtained, but
increasing the voltage past this point will cause
great problems as the buzzing completely stops,and the
readings go down to the 20 ma range. Increasing the
voltage to 150 volts will not allow the conduction to
go past that 20 ma reading of amperage, and something
is seriously wrong as the transformer no longer
produces this buzzing sound. Must be the ground fault
interruptor kicking in or something.

Unfortunately this transformer has what is known as a
ground fault interupter. Here is some info found in
instructions;
No 6 on the instructions specify the following;
Integral Plus comes complete with a three wire
grounded cord and plug. (Note; I did not recieve such
a plug. The input of the primary consists of a white,
black and green wire. I merely connected the
white and black wires to the variac with amperage
meter in series, and did not ground the green wire.
Undoubtably the lack of a ground is causing some kind
of problems.) The third prong of the plug,
(ground prong), (which I did not recieve), must not be
cut off. The receptacle must be properly grounded. (
The next step will obviously be to ground the green
wire to the third post on the plug receptacle
itself on the isolated output of the variac) Defeating
the grounding system could result in a hazardous
electric shock situation.

Next I inserted the ground wire at the variac plug
receptacle. A 24 inch argon bulb was run in series
with a 20.5 mh larger solenoidal coil form used for TC
experimentation. When running the bulb alone, it fires
about 130 volts variac. However at the lower voltages
prior to firings, a vibrational noise can be heard
coming from the transformer. After the bulb is lit
with a stable, non flickering plasma discharge, about
590 volts is read from a needle analogue voltage
meter, across the bulb, and these vibrational noises
completely cease. Adding this coil in series with the
bulb will then reduce the voltage to about 515 volts
across the bulb, with 140 volts across the coil, for
the same condtions of variac regulated primary input.

Scopings of the output show 18,000 hz, not the stated
20,000 hz. For the coil scoping, ringing appears on
the signal, corresponding to the resonant frequency of
the coil. ALL NST's despite their stated voltage
rating only deliver enough voltage across a bulb
necessary for the bulb to ignite and continue its
plasma discharge. This is generally in the 550-650
volt range for  standard 24 inch length bulbs.

I cant say for sure in the case of NST's, but in other
bulb studies, increasing the amperage through the bulb
to make for better illumination, is not accompanied by
a corresponding increase of voltage across the bulb,
rather it works in reverse, the higher illumination
will cause less voltage to appear across the bulb.


 > I know that they are not suitable for TC power work,
 > but I have a custom
 > xenon filled snake tube that currently uses a
 > similar 9 KV SS supply, and
 > is operating intermittently, perhaps because of gas
 > cleanup, or a very slow
 > leak.  Whatever the cause, the discharge goes fuzzy
 > at times, or fails to
 > completely arc across the 48" tube.  If I run a hand
 > along the outside of
 > the tube, I can usually get the discharge to operate
 > properly again, at
 > least for a minute or two.  I'm betting that a
 > hotter supply would make the
 > tube run again, at least for a while.
Sounds like the only redeeming quality for these
transformers would be the higher output frequency. The
higher frequency generally makes for a lower point of
voltage firing for the gas bulb. A 4 inch neon that
still takes about 500 volts to fire at 60 hz, will
fire around 250 volts with this transformer.  These
differences are less drastic with longer bulbs
however.
 > I can easily rig an autotransformer to get 220 volts
 > for the input.  I
 > suspect that these use a switching type driver that
 > rectifies the input 110
 > Vac line input, and probably wouldn't care much if
 > it was seeing 50 Hz or
 > 60 Hz.
It does not. The transformer at primary acts
completely nonlinear in its amperage consumption,
where at 100 volts it suddenly starts taking
appreciable amperage, and increases exponentially for
the next 20 or 30 volts of added voltage. One actually
gets more primary amperage consumption with a bulb
then just a pure inductance of a coil, so again they
are exclusively intended for gas bulbs.  I dont know
if they could be used for jacobs ladders as the ad
suggests. It would seem to me that the effect of
seeing a short on the output would cause the ground
fault interruptor to kick in, but I dont know, havent
tried that yet. Also the output is not frequency
dependent on the frequency of input, which ordinary
transformers are. I have driven these transformers at
480 alternator frequency, and still obtained the same
18 khz output. The actually seem to have a smoother
operation at 480 hz, as the vibrational noises prior
to bulb ionization do not then occur, but they do at
60 hz.  HDN

  However, I thought I'd ask in case some had
 > an experience blowing
 > one up on 60 Hz power.
 >
 > Any experiences would be appreciated.
 > Thanks, Dave
 >
 >
 >
 >


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

_