Sciencemadness Discussion Board

neon transformer

bilcksneatff - 19-11-2007 at 15:13

Does anybody know how to make a neon transformer? If not, where I can get one?

12AX7 - 19-11-2007 at 15:33

I know how to make one, but I don't know why one would want to.

Try phoning your local neon sign supplier. Additionally, UTFSE. Finding NSTs has been hammered to death by the Tesla coil crowd, information is abundant.

Tim

[Edited on 11-19-2007 by 12AX7]

bilcksneatff - 19-11-2007 at 16:13

I was looking for a way to make NO2 gas. I would use the NO2 to make nitric and possibly sulfuric acids.

Would a Van de Graff generator work for this? I have a partially finished generator in my garage.

[Edited on 19-11-2007 by bilcksneatff]

Xenoid - 19-11-2007 at 16:38

Quote:
Originally posted by bilcksneatff
Would a Van de Graff generator work for this? I have a partially finished generator in my garage.[Edited on 19-11-2007 by bilcksneatff]


Not unless it's a bloody big one!

A homemade VDG might produce 500,000 volts at 10uA that's only 5 watts! Whilst they can produce spectacularly long sparks a VDG can only maintain relatively low currents.

If you can't locate a NST your best bet might be an automobile ignition coil. There are plenty of circuits on the web for driving these. Driving two of the old style coils wired in antiparallel can give a fairly "grunty" performance comparable to a NST.

Regards, Xenoid

bilcksneatff - 19-11-2007 at 17:06

Thanks, Xenoid!

12AX7 - 19-11-2007 at 17:18

You want a fat, hot arc, not a thin, wussy spark. Amps, not volts. You're going the wrong way. Try a carbon arc torch.

Tim

dann2 - 19-11-2007 at 19:22

Hello,

The transformers in microwave ovens put out 1500volts or there abouts. A few in series would up the voltage.
Theses things put out quite a few amps, are current limited (at a amp or so I think) AND ARE (FUk?*@$) LETHAL. [Probable not supposed to use that language but it is just to get your attention.] They have killed people who know alot more about electrics that most.

Dann2

Twospoons - 19-11-2007 at 20:52

Microwave oven transformers (MOT) are not current limited like a neon transformer (NST). So as soon as you strike an arc, you will try to pull the whole national grid through your wall socket (an exageration, but you get the idea). To use an MOT you will need an impedance (L or C) in series with the primary.

12AX7 - 19-11-2007 at 23:24

No, they are. Just not all that well.

NSTs have the same magnetic shunts in them that MOTs do, but MOT shunts are narrower --> less current limiting. The magnetron doesn't need too much current limiting, but an arc sure as hell does.

What you really want is an inductor, in series with the MOT primary, of about 20 milihenries, 10A capacity. This will be about the same size as an MOT, but built differently. You could also use an 8 ohm resistor (approximately a space heater's heating element), but then you're wasting power in the element that could be ionizing air instead. An inductance is lossless.

Tim

dann2 - 20-11-2007 at 11:22

Hello,

It is not a good idea to connect a microwave transformer to the mains directly without a load. The designer/manufacturer of the oven always knew there would be a load on the transformer (the Magnetron) and therefor could skimp on input windings. If you connect two (or three perhaps) of theses transformers together you may be OK. The primarys need to be connected in series, the secondarys go in series too.

This is dangerous stuff as the currents available are high.

Dann2

497 - 20-11-2007 at 12:17

actually from what i've read a high voltage low current is best. a high current arc puts a lot of energy into the electrodes and radiant heat which is wasted. the higher voltage makes an arc with more concentrated heat and a sharper gradient (very important to minimize decomposition of the NO. they tested all this back at the turn of the century. best yield i've heard of industrially was 950 kg HNO3 per kilowatt year (110 g per kwh.) on the other hand an MOT might be the best option simply because they're cheap and easy to get. a big NST would be better i think but i've heard they're pretty expensive.

bilcksneatff - 20-11-2007 at 12:27

There was a book somewhere that had plans for an "anti-gravity levitator." It had a complete schematic for a high-voltage transformer. I can't remember the output voltage though, probably was over 1kV.

12AX7 - 20-11-2007 at 15:08

Quote:
Originally posted by dann2
Hello,

It is not a good idea to connect a microwave transformer to the mains directly without a load.


Actually, this is not true for any transformer design I am aware of.

Switching power supplies often need a minimum load, on the other hand. Very different animal.


Quote:
Originally posted by 497
actually from what i've read a high voltage low current is best.


What I heard is, thin high voltage sparks, especially those giving mostly blue colors, are a result of oxygen breakdown and ultraviolet radiation, therefore giving plenty of ozone -- which smells like NO2, but most certainly isn't.

N2 + O2 <---> 2NO is an equilibrium and goes a bit to the right at high temperatures (even mere flame temperatures; ionization needn't enter into things here). Indeed, a high refractory resistive element alone might be used to heat air to approximately 2000C or so, with long life -- no sputtering to worry about. I don't know if you'd get as much yield as with an ionizing source.

Ya know, pressure is also something to consider. Isn't Le Chatelier's in favor of NO2, after all? Pump that sucker up to 10 atm or more. The arc needs more voltage then (now you have an excuse for an MOT or more evil things still), or a solid heating element could be used. Would also be simple to absorb in water, which could also be under pressure. In fact, you could use a bubbler pump inside the reaction vessel to circulate the pressurized air between absorbtion and reaction, and a source of compressed air supplies fresh air. A blowoff would of course be necessary to release excess nitrogen, argon and other unnecessary gasses.

Tim

[Edited on 11-20-2007 by 12AX7]

Tacho - 21-11-2007 at 02:43

Recently I have built an "arc generator" putting the two carbon rods in series with the primary winding of a big transformer (scrap) and then removing the core's steel plates, a few at a time, until the arc was sustained with the right intensity.

In other words: I started with a big ballast and made it less inductive in steps until it suited my needs.

Beware that the primary winding must be made of thick wire to prevent overheating, and I have 127V in my mains. At 220 or 240V you are taking much higher risks.

dann2 - 21-11-2007 at 18:33

Quote:
Originally posted by Tacho
Recently I have built an "arc generator" putting the two carbon rods in series with the primary winding of a big transformer (scrap) and then removing the core's steel plates, a few at a time, until the arc was sustained with the right intensity.

In other words: I started with a big ballast and made it less inductive in steps until it suited my needs.

Beware that the primary winding must be made of thick wire to prevent overheating, and I have 127V in my mains. At 220 or 240V you are taking much higher risks.


Hello,
Do you mean, putting the carbons in series with the secondary?
Dann2

12AX7 - 22-11-2007 at 01:26

No, he is in fact using the transformer's primary winding as an inductor. An effective method, but wastes a lot of VA as well.

Tim

Tacho - 22-11-2007 at 02:32

Quote:
Originally posted by 12AX7
No, he is in fact using the transformer's primary winding as an inductor. An effective method, but wastes a lot of VA as well.

Tim



Exactly.

Check this forum for "arc furnaces" and you will find a couple of links to DIY arc furnaces that use an inductor as current limiting device to what would otherwise be a short-circuit. I used a transformer simply because it was the only heavy-duty inductor I had around and I was too lazy to wind one myself. I used the primary because it had thicker wire, that's all.

Xenoid - 22-11-2007 at 08:53

Dann2, if you feel like suicide because your LDO anodes keep falling apart, try making this from the 1930's......:o

http://blog.modernmechanix.com/2007/03/19/experimental-arc-f...

Regards, Xenoid

Tacho - 22-11-2007 at 10:30

Notice the fellow in the picture uses a smoking, bowtie, no gloves, and looks directly to the electric arc without googles.

Oh, and what would happen if that crucible full of white-hot molten metal tips over and splashes over his lap?

Lovely picture indeed.

[Edited on 22-11-2007 by Tacho]

Xenoid - 22-11-2007 at 11:00

Yeah!... I love that image!

The guy looks like a cross between Howard Hughes and a stage magician!

And no goggles, even though the article warns that they should be worn!

Regards, Xenoid

Anti-gravity levitator

JohnWW - 23-11-2007 at 21:00

Quote:
Originally posted by bilcksneatff
There was a book somewhere that had plans for an "anti-gravity levitator." It had a complete schematic for a high-voltage transformer. I can't remember the output voltage though, probably was over 1kV.

For that item, try:
http://www.techkits.com/
http://www.makezine.com/extras/31.html
http://www.greatdreams.com/scalar.htm
http://antigravity.altervista.org/levitus.html

Also look up "Otis T. Carr" on Google. He based his invention in the 1950s on Tesla's work.

[Edited on 24-11-07 by JohnWW]

dann2 - 25-11-2007 at 17:24

Hello,

From 'Coil design and construction manual' by B.B. Babani

Enjoy!!!!!!!!!

You may need to go to WWW.LIZARDTECH.COM for to get a reader for this type of doc.

Dabb2

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