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franklyn
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| Quote: | Originally posted by Flip
I built an ozone generator three or four years ago that was capable of turning
methanol blue at -40 deg C by complexing with the solution, the O3-methanol
complex will begin to form and the solution will turn a light shade of royal blue |
Is this a good idea, how safe is this ?
CH3OH and oxidizers don't usually play nice together,
even at the temperature of dry ice.
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roamingnome
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These links might be intersting for ozone use
I was most happy to find Lindlar's Catalyst preparation, which at first seems off the point but bear with me.
www.uni-leipzig.de/~nmr/STB/Publications/ozon.pdf
www.freepatentsonline.com/5039737.html
http://www.ch.ic.ac.uk/local/organic/12.html
Excerpts from the above:
EXAMPLE 2
156 g of styrene in approximately 850 ml of methanol were treated with ozone as described in Example 1, whereby approximately 1 liter of a 1.5 molar
peroxidic ozonolysis solution was obtained; this solution was treated with hydrogen in a device as depicted in the illustration at a temperature of
30.degree. to 40.degree. C. and a pressure of approximately 0.12 MPa in the presence of a metallic monolith catalyst coated with a Lindlar catalyst
basic substance. The absorbed hydrogen amounted to 31.9 normal liters, or 94.9% of the theory. After completion of the reaction, the diluting agent
was evaporated and the residue was vacuum-distilled. At a boiling point of 119.degree. to 120.degree. C./14 mm of Hg, 149.3 g of benzaldehyde, or
approximately 94% of the theory in relation to the employed styrene, with a purity of virtually 100% were obtained.
Lindlar's Catalyst (5% Pd on CaCO3, poisoned with Pb)6
Stir calcium carbonate (precipitated, light; 1.1 g) in water (10 ml) in a flask which is fitted with a thermometer and mounted on a magnetic
stirrer/hotplate. Whilst continuing the stirring, add palladium chloride (90 mg) to the suspension and after 5 min., raise the temperature to 80deg.C
for a further 10 min. Cool the mixture and transfer it to a hydrogenation flask, using ~ 10 ml of water for rinsing. Hydrogenate the mixture until
hydrogen absorption (10-20 ml) is complete (ca. 15 min); the hydrogenation procedure is described below. Collect the reduced catalyst on a small
'Hirsch' funnel (Whatman filter paper No. 1) and wash the catalyst with distilled water (20 ml). Add the damp catalyst to distilled water (10 ml) in a
flask on the magnetic stirrer/hotplate. Switch on the stirrer, add a 5% (w/v) solution of AnalaR lead acetate in water (2 ml) and, after 10 min.,
raise the temperature to 90deg.C for 40 min. During this time, add distilled water, as necessary, to compensate for evaporation losses. Cool the
mixture, collect the catalyst on Whatman No. 1 paper in a small 'Hirsch' funnel and wash the catalyst with distilled water (total, ~ 50 ml). Transfer
the catalyst to a clean, tared, specimen tube and dry the catalyst in a pistol at 40deg.C to constant weight (~ 1-3 h). Crush the dry catalyst to a
powder with a clean spatula or glass rod and stopper and label the tube (catalyst yield: 0.9-1 g).
And for the truly inquizitive
Towards the catalytic application of a monolithic stirrer reactor
http://repository.tudelft.nl/file/321784/202260
methanol some how becomes formaldehyde, but im not totally sure yet. theres a level of danger in most things
[Edited on 24-11-2006 by roamingnome]
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Natures Natrium
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http://www.valdosta.edu/~tmanning/research/ozone/
A wonderful site with a motherload of presifted US ozone related patents, sorted by type of ozone production (electrochemical, UV, discharge, etc).
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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roamingnome
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acording to this page Natures Natrium
http://www.valdosta.edu/~tmanning/research/ozone/
Does only one plate of the ozone device need to be gaped?
My NST transformer does not designate + or -
Can a cheapodepoto voltage tester be used on high voltage becuase its low amps?
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Natures Natrium
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| Quote: | Originally posted by roamingnome
Does only one plate of the ozone device need to be gaped? |
-I'm not sure what you mean. The gap is the relative distance between two objects, you only have two plates (right?), so how can one "be gaped" and
not the other?
| Quote: | Originally posted by roamingnome
My NST transformer does not designate + or -
Can a cheapodepoto voltage tester be used on high voltage becuase its low amps? |
-I have no idea, but I would guess yes. I havent touched a multimeter since I was a child. I really need to pick one up one of these days.
It does matter though if using a design like Flip's, as you want a "negative corona" discharge which produces more ozone than the "positive corona"
discharge.
http://en.wikipedia.org/wiki/Corona_discharge
This is where my understanding gets fuzzy though, as it seems that oxygen should make contact with the negative, so the negative should be the rod in
the center, but it also seems like all the information I have implies that the type of corona is decided by the coiled electrode.
This is all a moot point though, when using plates, and that strikes me as yet another powerful advantage over the tube type. Im not really willing
to mess with trying to build a flyback driver, expecially if that will only bring the efficiency up to the same level as a system with no dielectric,
which it seems to me would be easier to contruct with plates rather than tubes.
If some of you electrohobbiests out there could chime in and correct any mistaken notions you see, I would be ever so grateful.
-NN
EDIT: DO NOT USE YOUR CHEAPO METER. I was at the hardware store, and it looked like most of them could not take over 660V.
[Edited on 26-11-2006 by Natures Natrium]
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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Natures Natrium
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Weee! :-)
Silly I know, as all I have done is make a simple corona discharge, but it was somehow extremely exciting to smell that ozone smell, and it is my
first time working with HV. Also, I now know my transformer works just fine. :-D
Im also starting to think that using the alumina tube was a fantastic idea, although I will need to rework my center "rod", as I used a piece of 10
gauge solid core copper wire stuck through a stopper. I straightened it the best I could, but there was a noticeble difference in strengths of corona
along its length. For the outside I had intended to use a thin wire coiled about 5mm apart, but I actually had trouble finding wire small enough. So
for this proof-of-concept run I just used some aluminum foil, and it worked extremely well. I think I may just use my copper foil for the outside
wrap on the next run. For the inside I might go ahead and find some larger diameter copper tubing, once I am confident of where my arc gap is, if it
can even arc through the alumina at all.
This was a real "jump up and down and clap with glee" kind of thing for me. Reminds me why I love science so much. And so much more to do and learn
as well! 
-NN
EDIT: Moving the solid core wire around with a plexiglass handled screwdriver covered in rubber tape, I was unable to get an arc formed, and there
was a noticeble change in the sound of the corona that made it sound more intense (louder). I think I might try to leave a gap between the copper
tube and the aluminuma sheath of ~1-2mm to pass the O2 through, if I can find convient enough parts to do it. Thoughts? Anyone have any?
[Edited on 28-11-2006 by Natures Natrium]
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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roamingnome
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Well it looks like you got yourself some ozone production. Getting that gap where you want it sounds tricky though. I finally got to the point of just
plugging my apparatus in as well.
To clarify my other point, you are correct in saying that between to plates there is only one gap. In the parallel plate ozone setup two
“electrodes” are sandwiched between a piece of glass creating two gaps. I decided to air gap one and sandwich the other.
At first nothing was happening and it appears that my over all surface area for electrodes was too large for the NST. So I took some scrap pieces and
crudely clipped them to the NST between glass and presto… purple coronas with lime… of course the uneven surface quickly heated up and cracked
the glass, but I got proof of concept.
Using that alumina tube for a molten sulpher battery might even be a cooler use, since that’s what they actually use for those high temp yet
powerful batteries.
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Natures Natrium
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| Quote: | Originally posted by roamingnome
To clarify my other point, you are correct in saying that between to plates there is only one gap. In the parallel plate ozone setup two
“electrodes” are sandwiched between a piece of glass creating two gaps. I decided to air gap one and sandwich the other.
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Ah, I see what you are getting at, unfortunately I still do not have an answer. 
I have been playing around with the electrode inside the tube, trying different materials and shapes to try and create the largest amount of corona
discharge without it actually arcing. My understanding is that a discharge is a purple streamer that tends to appear to be a steady "flame", whereas
an arc is a bright blue-white "bolt" that tends to dance a lot. Note that there is no airflow in the tube, it is sealed at one end and open at the
other for observation.
The thin, 10 gauge copper wire provides nothing but steady, small purple jets that do not reach the alumina tube. The overall quantity of jets and
individual size is relatively small, and the set-up produces a light buzzing noise. (All the sounds are amplified greatly by the open-ended ceramic
tube).
I took some ultra-fine steel wool, and rolled it up (like making easy clay snakes), and pierced it lengthwise with the copper wire. This gave the
length of the wire an effectively fuzzy physical diameter of about 2 cm (inside the ~26mm ID tube). The effect of this was quite drastic. The sound
increased 4x, and looking into the tube the number of jets had increased by about ~20x, although the intensity had not changed much. A strong smell
of ozone became apparent much more quickly than with the wire alone. There was, however, an occasional dancing bolt, particularly close to the center
where the alligator clip was on the outside electrode (more on that IAM). Whereas the wire produced almost zero heat, this slowly became warm within
a minute.
Next I tried wrapping aluminum foil tightly around the fine steel wool, shortening its physical diameter to ~16mm. With this setup the sound dimmed a
bit, and the number of jets lessened, but the intensity of the jets seamed to increase a bit, and there were several that I had trouble
differentiating between arcs and streamers. They werent terribly bright, and they were purplish, but they tended to flicker back and forth between
one or two points.
Last, I tried drilling a hole through a new stopper, and shoved through it an old 3/8" masonary bit I have. I shoved it through so that the tip of
the bit was outside the tube and made a convient place to clip on to. The supposition I had in mind was that a smooth, larger analogue to the copper
wire would be ideal. I was suprised to see that number of jets appeared to be less than the copper wire, although they were much more intense
individually, particularly where the bit ended in the tube, as the bit was marginally wided there.
So, I still havent found an ideal inner electrode, and the best I have come up with seems like a bad choice both intuitively and logically (the
ultra-fine-steel-wool wrapped copper wire). At the very least, I can imagine that it will have to be replaced on a regular basis, although it showed
no signs of oxidation or decay from my brief experimentation. On the other hand, the rubber stopper is faring less well, as the surface that is
inside the tube during operation is already cracked (though oddly it is still very flexible and rubbery).
Oh yea, and for the outer electrode I switched to very carefully and tightly wrapped copper foil, secured down with rubber tape both at the ends and
along the outside seam (two layers of copper total). This alone lead to a very observable increase in both number and intensity of the jets coming
off the 10 gauge inner electrode wire.
I keep finding myself questioning whether or not I am actually creating a real "corona discharge", as it is called the "silent discharge method" and
my setup doesnt seem very silent to me.
I think, based on these observations, the ideal inner electrode would a 6mm wide solid copper rod with a very fine, high thread-count spiral carved
into its surface.
It also occured to me that higher pressures probably favor this reaction, since 3O2 -> 2O3 produces a drop in pressure, but I dont know how that
would effect the corona discharge, if at all.
Again, if anyone has any input or advice, please share.
-NN
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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Higher pressure insulates better.
The smaller the radius of any surface, the higher the electric field at that point (assuming it's open to opposing charge, of course). This is easily
seen with Gauss' law, since for some regular charge enclosed inside a spherical Gaussian surface, the shape of it does not matter. Similarly, the
force of gravity at the distance from Earth's center to its surface is the same regardless of whether the Earth's mass is in the form of a huge
spherical rock or a compact ball of neutronium. However, at the surface of the object, the field is much more intense. Air breaks down at a certain
(if variable!) electric field. You can put 20kV on a big smooth sphere without any breakdown whatsoever, or you can put 20kV on a sewing needle and
get a big flame of corona (but obviously, no bigger than the smallest sphere that won't break down!).
Since you want breadth as well as electric field, some smooth plates (possibly perforated, but mind that they are deburred), stacked and charged
alternately, with air/oxygen flow across or through them, should get you there. With high frequency (FBTs with HV diodes need not apply), you can
also use insulators, which tend to prevent arcs, or form millions of low-energy sparks, which is fine enough for the goal.
Tim
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Natures Natrium
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Ok, so if I may use extrapolation as a means to verify my understanding...
| Quote: | Originally posted by 12AX7
Higher pressure insulates better. |
For my situation, high pressure is more likely to be detrimental than helpful, not to mention it would add to design complexity. I can imagine large
power sources (30kV+) could take advantage, but I am only using a 10.5kV NST.
| Quote: | Originally posted by 12AX7
The smaller the radius of any surface, the higher the electric field at that point (assuming it's open to opposing charge, of course). This is easily
seen with Gauss' law, since for some regular charge enclosed inside a spherical Gaussian surface, the shape of it does not matter. Similarly, the
force of gravity at the distance from Earth's center to its surface is the same regardless of whether the Earth's mass is in the form of a huge
spherical rock or a compact ball of neutronium. However, at the surface of the object, the field is much more intense. Air breaks down at a certain
(if variable!) electric field. You can put 20kV on a big smooth sphere without any breakdown whatsoever, or you can put 20kV on a sewing needle and
get a big flame of corona (but obviously, no bigger than the smallest sphere that won't break down!). |
Alright, there are a lot of factors to take into account here. So it seems that the electrical field generated by a specific voltage is independent
of electrode size, as long as the electrode maintains the same shape (and maintains the same distance from opposing charge?), but the field is still
more intense at the surface as long as the largest possible size for the electric field hasnt been exceeded by the physical size of the electrode.
| Quote: | Originally posted by 12AX7
Since you want breadth as well as electric field, some smooth plates (possibly perforated, but mind that they are deburred), stacked and charged
alternately, with air/oxygen flow across or through them, should get you there. With high frequency (FBTs with HV diodes need not apply), you can
also use insulators, which tend to prevent arcs, or form millions of low-energy sparks, which is fine enough for the goal. |
This also appears to confirm what Martin was saying about the need to use a flyback. Im not neccesarly opposed to the either the use of a flyback or
the removal of the diaelectric, but I was trying to avoid any sort of plate design. The use of plates introduces a number of basic design
complexities, including the need for a non-conductive, ozone resistant, and very probably rectangular enclosure. The only materials that are
available for me that meet the criteria are glass, lucite, and PVC. I am not capable of working with glass that well, and lucite and PVC have limited
tolerence to ozone (plus PVC is hard to find around here except in tube form).
However, my bottom line goal for this project is to create a device capable of outputting >5g O3 per hour. To this end I will modify my approach
as needed.
As an aside, has anyone ever calculated the amount of ozone that the "commercial unit" depicted in Vogel's 3rd ed. produces? 170mL of O2/min @ 7%
(maximum) O3 content = 10.2L/h = 714mL O3/h = 31.9mmol of O3 or 1.53g/h O3. At that rate it would take 33 hours just to reach one full mole of O3.
OTOH, some of the modern models being hawked on eBay make claims of 28g O3/h, which would reach one full mol of O3 in about 1h45m! It is my sincerest
hope that 5g/h is not an unreachable goal for a home built apparatus.
I am going to go play around a bit more, maybe test how close two sheets of flat aluminum foil can get before they arc. Not to say I am giving up on
the tube design just yet. I cant help but wonder how using a sheet of copper instead of a tightly wound copper wire as the outside elctrode effects
the discharge. Will try variations on that too. Last, I need to find a convienent source of a pure alkene (I was thinking about isolating some leaf
alcohol for the purpose, but it became winter too quickly) to use as a means of determining the efficiency of the design.
-NN
EDIT: Hmm, this plates with no dielectric thing could be tricky. There was a distance where I noticed a physical hum-like vibration, but no arc was
drawn. The aluminum foil covered pieces of cardboard clearly moved a bit due to thier attraction to each other. However, keeping the plates as close
to each other as possible without drawing an arc produced NO smell of ozone. Considering this stuff is blatently pungent in the ppb range, I am not
convinced that using an uncovered plate is a viable method at all. OTOH, tilting on plate about thirty degrees away from the top edge and drawing an
arc on the bottom edge produced a rather neat Jacobs Ladder effect. BzzzzZZZT! 
[Edited on 2-12-2006 by Natures Natrium]
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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Natures Natrium
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Essentially finished contruction of tube design. Using a water aspirator to draw air through the inlet, and through a small RBF containing a spatula
tip of NaI in tapwater (used HDPE tubing through-out, is supposed to be as good or better than lucite ... hmm), the ~30mL of water quickly turned
amber orange in a matter of 20s or so, and ceased any other visual changes despite another 5m or so of "ozoning". On pouring down the drain (diluted
with running water), the smell of iodine was evident. Now I know what I already knew, that this setup is producing some ozone. Now to try a
positive pressure setup using pure O2. Oh yea, and the rubberstoppers at either end are coated with teflon tape now, dont know how well that is going
to work out yet.
After the five minutes or so, even with an airflow of RT air, the tube became quite warm. This is something I kind of expected to happen, but hoped
would not. It seems some sort of cooling is absolutely essential to making a design such as this work. Ideally the coolant would function as an
electrode (as per garage chemists work), but I am not too comfortable with a bucket of (salt) water with a 10kV charge on it. The only other thing I
can think to do would be to draw (or push) the O2 through a copper tube coiled at the bottom of an acetone/dry ice bath. Not exactly condusive to
easy, portable, and continual operations, but might be necessary to reach that 5g/h goal.
EDIT: Ive not seen any specific design elements used to reduce the heat problem in a multi-plate system. Is it not an issue?
[Edited on 3-12-2006 by Natures Natrium]
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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garage chemist
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If you want to determine the ozone output of your design, you can do it with iodide solution. Just remember that it has to be acidified with at least
1 mol HCl per mol iodide, as the oxidation of iodide with ozone produces hydroxide ions which will react with your iodine as soon as their
concentration becomes high enough.
A NaI solution without acid added is not suitable for ozone determination!
The liberated iodine can be titrated with sodium thiosulfate or sodium sulfite solution, making possible the direct calculation of the output in mol
O3 per measured gassing time.
In my setup, the salt water was of course grounded, and the wire inside the glass tube was the live electrode. I also wouldn't like to have a bucket
of electrified salt water on my table. But with an NST which has a center-tapped secondary that's not possible.
You see, with a flyback as the HV source you have the advantage of added safety.
Also, with the flyback the ozone output of my setup was very much increased in comparison to the NST I also tried. It seems that the ozone production
increases with increasing frequency of the HV source.
I used the Powerlabs flyback driver, it's the best one I've ever used, much better than any IC-based oscillators.
I recommend that you try the tube design with 7mm OD tube (or slightly larger) in saltwater and flyback as power source.
The ozone concentration at the output of my setup was so high that it burned my nose and eyes like bromoacetone vapors.
Do you have a supplier of glass tubing?
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Natures Natrium
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| Quote: | Originally posted by garage chemist
If you want to determine the ozone output of your design, you can do it with iodide solution. Just remember that it has to be acidified with at least
1 mol HCl per mol iodide, as the oxidation of iodide with ozone produces hydroxide ions which will react with your iodine as soon as their
concentration becomes high enough.
A NaI solution without acid added is not suitable for ozone determination!
The liberated iodine can be titrated with sodium thiosulfate or sodium sulfite solution, making possible the direct calculation of the output in mol
O3 per measured gassing time. |
*nods* The raw NaI was meant as a qualatative test.
| Quote: | Originally posted by garage chemist
In my setup, the salt water was of course grounded, and the wire inside the glass tube was the live electrode. I also wouldn't like to have a bucket
of electrified salt water on my table. But with an NST which has a center-tapped secondary that's not possible. |
Hmm, by center tapped secondary, do you mean the secondary ground fault protection, or something else relating to the actual transformer? Sorry, my
knowledge of electrical engineering is severly limited, but I am working on that.
| Quote: | Originally posted by garage chemist
You see, with a flyback as the HV source you have the advantage of added safety.
Also, with the flyback the ozone output of my setup was very much increased in comparison to the NST I also tried. It seems that the ozone production
increases with increasing frequency of the HV source.
I used the Powerlabs flyback driver, it's the best one I've ever used, much better than any IC-based oscillators. |
Well, I just spent money on a NST, and I think I will finish experimenting with that first. I have never really built a circuit before short of the
one I just did, (get it? ), so I had some hesitancy about messing with this.
However, I am now sure it is something I could do, but it requires more parts, and my budget is pretty limited right now. For one thing, there is no
way in hell I am straight up using a battery, I will find a mains to 12+V DC converter first. Second, the majority of flybacks, at least on 'ole
ebay, dont appear to be ones suitable for this task. You say you used the powerlabs design, but were you able to procure a flyback like that monster
he was using? Given more time and money I will probably build one, but right now I am going to seek to enhance my current design (get it? ) until I reach a good balance of ease of use and optimum efficiency.
| Quote: | Originally posted by garage chemist
I recommend that you try the tube design with 7mm OD tube (or slightly larger) in saltwater and flyback as power source.
The ozone concentration at the output of my setup was so high that it burned my nose and eyes like bromoacetone vapors.
Do you have a supplier of glass tubing? |
Most of the stuff I have is smaller diameter, from a local shop. I also know a neon sign artist that could probably hook me up for a reasonable
price, if I were to inquire. I wonder, would my ceramic tube hold up against water? I am somewhat inclined to believe that it would not, although I
have never even gotten it wet.
Also, there is a (relatively small) part of me, the empirical part you could say, which is demanding some hard numbers for comparison. I think I will
have to run a battery of tests (get ... nm), and see what sort of ephemeral conclusions I can come up with. I wonder, you mention that your design
had a very high output, higher with the flyback, but did you ever quantify an actual value from either design? Im not trying to put you on a "hot
seat" or anything, I am just curious.
As an aside, I have never smelled or seen bromoacetone, but I am willing to bet it couldnt be too much worse than the time I accidentally gassed my
lab with methylchlorosulfuric acid.
-NN
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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Natures Natrium
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Wow, ok, I found out what I wanted to know:
"In general, when an alternating current voltage is applied to a sample of oxygen, ozone production doubles as the frequency of the current is
doubled. The amount of ozone generated varies exponentially with the applied voltage." Ref at bottom.
The design they used was capable of producing 2mmol of O3/h (~.1g), however even knowing what they knew they still used a custom circuit with a
frequency of only ~60hz @ 15-25kV. When they cooled the electrode to -20C and chilled the feed O2 to ~-150C, they were able to pass the O2 through
much quicker (if that isnt a typo) and still reach concentrations of up to 10% v/v, which equals roughly 400mmol O3 per hour, or 19.29g. Thats a
damn big difference, which again makes me wonder about typos.
Thier design is also noteworthy, and I am looking to see how I might incorporate it into my own build.
Primary factors:
Temperature: The colder the better.
Voltage: The higher the better
Frequency: The higher the better.
Nothing I didnt already know technically, but at least I have some idea HOW much better, and it looks like high frequency is the only way to go.
Now, anyone know an easy way to build a 50kV@30kilohertz transformer? Oh, and
a really cheap liquid nitrogen maker would be great too.
-NN
REF is attatchment.
Attachment: ozone_generator.pdf (48kB)
This file has been downloaded 1412 times
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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Be careful around that LN2, don't want explosive crystals of ozone around. At least not in Technochemistry, but the forum below it  (Big OB% explosive, eh?)
For expense, you might cool the gas/apparatus with ice or refrigeration or dry ice, rather than CO2.
Tesla coil (F >> 100kHz) is pretty easy to rig up, a solid or vacuum state one is pretty nice too, efficient and quiet. Lots of sites out there
on the subject.
Tim
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Natures Natrium
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| Quote: | Originally posted by 12AX7
Be careful around that LN2, don't want explosive crystals of ozone around. At least not in Technochemistry, but the forum below it (Big OB% explosive, eh?)
For expense, you might cool the gas/apparatus with ice or refrigeration or dry ice, rather than CO2.
Tesla coil (F >> 100kHz) is pretty easy to rig up, a solid or vacuum state one is pretty nice too, efficient and quiet. Lots of sites out there
on the subject.
Tim |
Yea, I decided some time ago I was too sloppy to properly mess with the energetic materials. Neat stuff though, I do enjoy reading others exploits.
:-)
Indeed, I think Ice/Salt Water is the way I will go, also using it as electrolyte. Solves many problems with one go, but creates a new one: I am
probably going to need a custom glass apparatus, unless I come up with a brilliant innovation on the equipment I have.
I would love to build a tesla coil someday, but one step at a time, I think. I would have to say (IMHO) I think it to be a 50/50 tie between tesla
coils and lasers for the ultimate electric-orientated home built project.
By the way, as a source of power for the flyback, is there any reason I couldnt use an ATX PC power supply (350W)? It says right here the 12VDC line
is capable of supplying 16A, and since there is two seperate lines I am guessing 8A per each. If this worked it would sure be a cheap, convienent
means of getting that DC power I need.
-NN
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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On the PSU, the yellow, red, orange and black wires all go to the same respective points on the circuit board, you can look for yourself. They're all
too flimsy to handle rated current alone, so you should parallel them when running a heavy load. Indeed, the output should be capable of rated load,
but remember it also expects an even load between the outputs. The 5V output is regulated the tightest, which means the 12V output will sag perhaps
a volt or two under heavy load (not an issue for a cheezy flyback driver, of course).
Come on... a Tesla coil is too damn easy to pass up. It's little more than the flyback driver you have already.
Remember to put a nice big film cap across the power leads to the flyback driver...nothing worse than a spongy power rail, at high frequency!
Tim
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Natures Natrium
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| Quote: | Originally posted by 12AX7
On the PSU, the yellow, red, orange and black wires all go to the same respective points on the circuit board, you can look for yourself. They're all
too flimsy to handle rated current alone, so you should parallel them when running a heavy load. Indeed, the output should be capable of rated load,
but remember it also expects an even load between the outputs. The 5V output is regulated the tightest, which means the 12V output will sag perhaps
a volt or two under heavy load (not an issue for a cheezy flyback driver, of course).
Come on... a Tesla coil is too damn easy to pass up. It's little more than the flyback driver you have already.
Remember to put a nice big film cap across the power leads to the flyback driver...nothing worse than a spongy power rail, at high frequency!
Tim |
*nods*, Awesome, DC power supply found.
I managed to find a flyback with an exposed ferrite core, but it is pretty small, and the secondary is entirely cased in white plastic insulator, and
there are no less than 3 different leads coming out of the thing. I will post a pic as soon as I can find a digital camera. Also, the ferrite core
appears to be two distinct halves, with a long screw down the center holding them together. The item was manufactured in '89.
I managed to also find the transistor, and the 1w 270Ohm resistor, but the only 5w resistor I can find thats even close is also 270Ohm. Im assuming
that the difference in resistance here is very important, and cannot be substituted.
So much fundamentally I dont understand yet, it makes it difficult for me to do anything other than follow the design precisely, as I havent a clue
what substitutions might do to the overall system.
I will get around to a tesla eventually, but it is better to finish one project before starting another (which of course by me saying makes me the
worlds biggest hypocrit.)
Ok, and what exactly is a film cap, do you have a part number for a good one?
-NN
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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http://www.digikey.com/scripts/DkSearch/dksus.dll?PName?Name...
Or any similar part from junked electronics. There's a lot of them in things with switching supplies, for the same reason. Film means plastic film
stores energy. Either vaporized metal (i.e. metallization) or fine foil moves the charge to and from the plastic.
What schematic are you working from? Powerlabs'? That calls for 240 ohm 5W and 27 ohm 1W (the junction between the two resistors should also have a
capacitor to GND or +V). 270 ohm is close enough (for run of the mill electronics, figure 10% variation is okay). Since the two resistors form a
voltage divider, you might likewise increase the 27 to 30-33 ohm instead. In this particular case, anything from 10 to 47 ohms (like, give or take a
factor of 2-3) might work, mostly depending on supply voltage. You can parallel and series-connect resistors to get different resistances. (Power in
each distributes according to the resistance, if they are equal then Rtot = R / n (parallel) or R * n (series) and Ptot = P * n (either way).)
Tim
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Natures Natrium
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| Quote: | Originally posted by 12AX7
http://www.digikey.com/scripts/DkSearch/dksus.dll?PName?Name...
Or any similar part from junked electronics. There's a lot of them in things with switching supplies, for the same reason. Film means plastic film
stores energy. Either vaporized metal (i.e. metallization) or fine foil moves the charge to and from the plastic.
What schematic are you working from? Powerlabs'? That calls for 240 ohm 5W and 27 ohm 1W (the junction between the two resistors should also have a
capacitor to GND or +V). 270 ohm is close enough (for run of the mill electronics, figure 10% variation is okay). Since the two resistors form a
voltage divider, you might likewise increase the 27 to 30-33 ohm instead. In this particular case, anything from 10 to 47 ohms (like, give or take a
factor of 2-3) might work, mostly depending on supply voltage. You can parallel and series-connect resistors to get different resistances. (Power in
each distributes according to the resistance, if they are equal then Rtot = R / n (parallel) or R * n (series) and Ptot = P * n (either way).)
Tim |
Ah, awesome, thanks for the help. I have a couple of caps off the circuit board that the flyback came attatched to, round small ones rated at
3.3microF, 50v. These should work as well, yes?
As for the resistors, I ended up with a 270ohm 1W and a 240ohm 10W. I was informed by the helpful clerk that it would work just as well, and he
explained that the wattage was just the max the resistor could dissapate.
I learned I cant solder for shit, it really is an artistic technique.
The transistor has me unsure of myself. The dude from powerlabs talks like you have to insulate the transistor from the heatsink, but isnt the case
of the transistor point C (collector) in the design? It sure as hell looks like it upon examination, which means the return from the primary coil
should be able to be hooked to the heat sink as long as the transistor is not insulated from the sink.
Beh, I am starting to hit my saturation point for today, may have to kick back and play some video games for a bit, to let all this sink in.
-NN
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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Yes exactly, but then the heatsink is live. In grounded equipment you have to insulate the transistor or the heatsink, so the transistor is usually
insulated, for which hardware is made anyway. If you don't intend on licking it I suppose it's fine, but do mind stray wires as well!
That cap will work, if not better since it's bigger. 3.3uF is also a good size for tweeter crossovers, and mylar film is a whole hell of a lot lower
distortion than the bipolar crap usually used.
Tim
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Natures Natrium
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Oh good, one less thing I need to purchase. :-)
Hmm, any idea how high the voltage coming back off the primary gets? My understanding is this side of the circuit is relatively low voltage, and the
wiring that is soldered to the transistor is fairly standard 12 gauge rated to 600V. I will have to make sure my resistors keep thier distance,
though.
Im actually almost finished with construction, but because I am unsure of where the output on this flyback actually is, I will wait to power it until
I can snap a shot of it and post it here. I will have to borrow a friends digital camera in order to this, which probably wont happen until later
tonight.
Again, thanks for all your help, it has been invaluable.
-NN
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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12AX7
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Depends, a resonant winding will peak out at about double the supply, you don't have a capacitor to reign it in so you'll certainly get more than
that. I wouldn't expect more than about 20 times, or a few hundred volts peak (for a period of maybe ~10 microseconds, each cycle).
Output is always the thickest wire...it's the highest, eh? You can arc around to other pins (naughty, but...eh...) and see which gets the best
discharge.
Tim
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Natures Natrium
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The whole setup, minus the PSU.
The end of the flyback.
Hmm, I dont think overvoltage on the primary side of the flyback will be an issue then. I am going to have to go and pick up a cap after all, as the
one I salvaged not only had very short leads, but appeared to be cracked as well. I dont think I would have fired it up anyways, too tired.
I will say this though, considering I knew nothing about transistors, resistors, flybacks, or even soldering I still managed to buy and put this
together inside of a day. Of course, if it doesnt actually work, then that doesnt mean much. Will find out tomorrow.
-NN
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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garage chemist
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The flyback you have looks really good, definately better than mine (and yes, the monster flyback from Powerlabs is overkill for an ozone generator.
You don't need more than 10kV at those high frequencies to make a very efficient ozone generator).
Even the modern flybacks with dozens of different leads can be used, as long as enough of the ferrite core is exposed to wind the new primary on.
To find out which lead on your flyback is the second lead to the secondary, measure the resistance between the thick HV lead and all the other leads.
If there is a few hundred ohms, it's the right one.
[Edited on 5-12-2006 by garage chemist]
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