Rough & ready power supply for a spectral lamp

[dr pepper]

I'm thinking of using a VSB-2 argon spectral lamp in an ornamental project, the lamp has no electrodes.
Are these powered by capacitive coupling via high voltage, or is there some weird way of making them light.

 

[D.A.(Tony)Stewart]

My interpretation of the Russian Datasheet

If you don't mind creating 5kV electrodes on either side of the glass bulb perhaps which could be insulated, the 22 nF caps in series are 11 nF which at 50 Hz is around 250 kohm and current must be limited to around 20 mA or 30 max. When the noble gas arcs the voltage drops and the current limited by 20mA * 250k = 5kV.

You can try using an automotive ignition coil (autotransformer) with about 1k voltage boost with an audio sine wave (not a square wave) at 50 to 100 Hz and verify the voltage gain with a sig.gen Increase the frequency will increase the current, then you may use proportionally smaller HV -metal film caps to maintain the limit. use twisted pair magnet wire inside insulation or carbon resistive sparkplug wire with one side grounded to PE gnd or use a battery then both sides are unsafe. 100 Hz use 10 nF. then use 6kV.

If I were you, I'd hunt for a glow ball instead.

 

[FvM]

Are you sure that the posted datasheet is valid for VSB-2 spectral lamp? As far as I understand these are EDL (electrodeless discharge lamps), excitated either inductively by RF field or in a microwave cavity.

 

[D.A.(Tony)Stewart]

No I'm not sure

ППБЛ-3М was the 70's recommended power source shown here. http://lampes-et-tubes.info/el/el014.php?l=e
and defined by http://lampes-et-tubes.info/el/VSB-2.pdf as ППБЛ-3М

This was example of C coupled plasma tube excitation.

But you are correct about the generator using induction RF power, which I found now as;

https://old-lighting.ru/ru/content/ppbl-3m-razryad with the bulb sitting on top of the column and down into the coil.

this would be a safer way to excite the plasma with some directivity gain using 2 coils perhaps in the 21 or higher MHz range.

I'm pretty sure this not what he wants to do but that's how the Ruskies did it in the 70's

.

This what I recommend you get instead.

https://www.amazon.ca/TradeOpia-Lightening-Sensitive-Decorations-Effective/dp/B00MON71Z8

 

[dr pepper]

The datasheet rattles on about the lamp having to be in the vertical position.
I have a ebay special high voltage generator, not sure what it makes but it produces a 5mm spark so might be enough, to get 22mhz I'd need a spark gap and a tuned circuit with the coil being part of the lampholder, and a very special cap as the other half of the tank.
That last link on the subject was interesting I had not seen that one before.
And then again am I going to make x rays or something weird playing with this thing.

If I want a plasmaball I'll go to temu.

 

[D.A.(Tony)Stewart]

Generally, inert gas plasma tubes emit UV and at higher energy levels, shorter wavelengths like CRT & TV's did so they used leaded glass screens to attenuate the X-Rays

N. Tesla patented the UV plasma bulb, then 2 or 3 phosphors were added inside the tube to convert to lower energy, visible wavelengths.

Tesla, was the inventor of the modern Fluorescent tube and many other bulbs were later developed with the same inert gases triggered by HV current-limited ballasts, old ones with heaters and modern ones with quick-start and no heaters with shorted dual pins at each end using a common yellow wire and independent coils for each tube each current limited according to the tube specs. I love 48" T8's and T5's 8/8" and 5/8" diameter with tri-phosphor true daylight 4000~5000'K options and they last 50 khrs with 86 lumens per watt.

5mm spark @ 3kV/mm is 15 kV but not current limited, then you need to create the E-field with electrodes bigger than the gap.

I found the old style car autotransformer as a useful tool for generating sine HV in the audio band up to 20 kHz but the inductive dual coil method looks to be a better way. with an enclosed Faraday shield to protect your eyes from getting cataracts or bloodshot eyes even with a few watts in the 470 MHz band. So you could consider an RF coil but the geometry of low ESR and heat dissipation is challenging.

but then you don't need this much power. This was intended for iron and not plasma so 4 kW at 75 kHz is not high enough frequency to excite some hundred femto-farad gas tube. This was just an illustration of how not to.

(not my design)

.

--- Updated Dec 5, 2023 ---

I just noticed in the coil design of 8 turns in 30mm OD in his lower left corner, he used 0.004 H which is too high and looks more like 1 uH so 0.5 Ohms at 80kHz or 500 Ohms if you used 80 MHz. Then skin effects add resistance.