Negative ions generator capacitors type!

[leaualorin]

Hello again!
I have in plan for sometime now to build a few negative ions generators but after looking for schematics and simple ways of generating negative high voltage(5000 volts) , I am more confused than ever!
I was going to build a cockcroft-walton circuit with 1n4007 diodes and X1,Y2,polypropylene,suppression capacitors of 33nF...
Now after a few thinking I got to the conclusion that these capacitors will not last long because after a few stages the voltage developed will be far above the ratings for a X1/Y2 capacitor, even though they can withstand 5Kv for a few seconds!
What do you all think?
A ceramic capacitor rated for 2200pF and 10kV would act and do the same as the polypropylene suppression capacitor?
I mean, will it STILL WORK and generate negative ions or I'm wasting my time here on this subject?!
Thank you kindly and I hope someone with more experience can clear things up for me!
Good day!

 

[FvM]

I don't understand the problem. In a standard cockcroft-walton circuit, no capacitor needs a higher voltage rating than the input voltage peak-to-peak value, because all capacitors are series connected. If it's different in your circuit, choose another one.

Cockcroft

 

[leaualorin]

Very fast response!
Well it's not different in my case; it's a classic cockcroft walton but I was thinking that after 2-3 stages the voltage will pass the maximum rating for a X1 , Y2 capacitor!
This is one of the schematics that I want to build :

I really don't want to get it wrong and make it work from the begining (not only a big "bum" noise and that's that...).
Do you have any other sugestions for generating negative high voltage?

 

[FvM]

Your doubts are unfounded. Just consider, how the circuit works.

Do you have any other sugestions for generating negative high voltage?

No, why?

 

[SherpaDoug]

The capacitor only "sees" the voltage across its two terminals. Don't pay attention to the voltage to Earth...or Mars for that matter! Each capacitor will only see the input 220VAC, or a little less as the losses add up.

 

[dick_freebird]

I have made a negative ion generator with nothing more than a
car ignition coil, a TV high voltage diode and a chattering relay.
Throws enough breeze for you to feel it a few inches away.
Let the coil do the work, says I.

 

[leaualorin]

@FVM : I always ask for better solutions or look/search until I get tired

@SherpaDoug : I will try to be reasonable and listen to the advices of those more experienced :razz:

@dick_freebird :
" I have made a negative ion generator with nothing more than a
car ignition coil, a TV high voltage diode and a chattering relay.
Throws enough breeze for you to feel it a few inches away.
Let the coil do the work, says I. "

I had in mind and that option , I have a fly-back transformer from an old japanese CRT monitor, two induction coils from some cars , a neon transformer but I'm not sure about the high voltage (beeing to high and generate too much ozone)...

I must say I studied this "negative ions thing" quite a lot and maybe that's why I got to the point where I have more questions than answers...

On one site/source a guy says that using capacitors with bigger capacity(100nF-220nF) will produce more negative ions , in the US Patent 4816684 it says that the 3500-4000volt limit musn't be passed otherwise too much ozone will be generated , but it uses a transformer AND A CW circuit...
Make an ioniser.


A guy on youtube that makes a lot of CW "toys" says , and I qoute from the original message:
YouTube - ‪prototype9000's Channel‬‏
" bigger capacitor means more nitrogen smaller capacitor higher frequency more ozone negative ions the higher currents will vaporize the metal turning it into nitrogen although microscopic you dont need much to make nitrogen gas you dont want to breath that so go with a smaller capacitance for more rapid oscillations in the circuit keep it cooler. or just calculate for input current "

I must order online all the parts and I'M SINCERELY CONFUSED...
What schematic/circuit type should I build?!

Other guy made a negative ions generator with a fly-back transformer here :
High Current: Make a Simple, but, Powerful Air Ionizer!!

I must say that the one part from the US patent 4816684 I allready made it from copper and 25 mm very sharp needles( the electron optics).
Anyway :
every little bit of advice is welcomed!
If someone wants to "study" this very interesting patent from 25 august 1987 can take it from here :
High-powered negative ion generator in a gaseous medium with a high-strength electric field configuration - Breton, Jacques L. G.
I allready xerox-ed it just to be sure I have it on paper!

 

[mtwieg]

You could put a stepup transformer after the mains, allowing you to need less doubling stages (though they would need to withstand more voltage).

 

[FvM]

I always ask for better solutions or look/search until I get tired

You have been initially asking for simple ways, thus I think the 50 Hz cascade multiplier is just O.K. High frequency switchers offer smaller form factors of course.

 

[leaualorin]

FvM , please give a schematic of some sort so I can "chew" something and try to make up my mind until July when I can order the parts needed from www. www.tme. eu

 

[leaualorin]

You could put a stepup transformer after the mains, allowing you to need less doubling stages (though they would need to withstand more voltage).

Are you reffering to the US patent schematics mentioned by me?

 

[mtwieg]

Are you reffering to the US patent schematics mentioned by me?

Well it has a transformer for isolation, not step up (at least it doesn't say so). I was suggesting making a HV transformer to immediately step up to, say, 600Vac, giving about 850Vdc at the first rectification stage. So you would need less than half the number of doubling stages (but each would have to tolerate 850V instead of 340V). If you have components that can tolerate higher voltages, then it makes sense to use a higher AC source voltage.

Also, having a variac first would give an easy way to vary the output voltage.

 

[leaualorin]

Well "folks" , I made an order yesterday at tme. eu for 100 WIMA MKS polyester capacitors ,100nF, 400VAC, 1Kv DC and 100 1n4007 diods,1A !
I'll listen to FvM and build a simple CW 10 stage and see what's the result in negative ions generating "power" !
I can only hope it will work and not make a loud bang !

I'll keep you informed but it seems that the darn things will get in my hands around the 7 july...
better later than sorry :roll:
See you later!

 

[leaualorin]

SUCCES!
I build a 11 stage (22 capacitors)CW last evening/night (I finally collapsed at 1:55 in the morning...) .
The "problems" are as followed :
During testing (live 240V AC , actually 250VAC measured) with no 10 Mohm resistors on the HV output side , I only get 1 needle to have that "purple" thing in the tip!
Is the CW too weak the capacitors beeing 100nF/400VAC WIMA or are the losses too big?
I purposely made an aray of pins (36) on a sheet of galvanized tin of size 10 cm by 20 cm and I must say it is preety disapointing to see only one pin having that corona discharge on the tip ,and the rest of them NOTHING!
The test was made in really dark conditions!
What are your suggestions?
:?:
P.S. ; I made a glass container for the CW and intend to immerse it in 110Kv oil for better working but I really want the opinions of those more experienced in these things this beeing my first CW !
Thank you!

 

[FvM]

I don't know what is "too weak" for this application. You can calculate an output resistance in a 100 Mohm and loaded output currents in 10 uA order of magnitude with 100 nF capacitors. Do you know your current requirement?

 

[leaualorin]

The curent should be 30 microamps per needle!
I intend to use 36 needles so I guess the curent would be 1,08 miliamps...

Right now I'm beeing "carefull" because I really didn't find those darn two 10 Mohm resistors wich should be on the HV output to limit the current (according to the schematic) , and use it without resistors (kind of dangerous...)
The most nerve-racking thing is that in complete silence it makes a "hissing sound" so that's a "sign" IT WORKS!
So why doesn't ALL the 36 needles have the corona on their tips?!
In the meantime I added another stage so now there are 24 capacitors ; and this is the maximum that the glass "box" allows(length) in wich the CW should "sit" immersed in 110Kv transformer oil...
I also calculate according to the formula :
"Eout = Ein * √2 * n
Eout is the output voltage
Ein is the RMS input voltage
n is the number of stages in the multiplier"

and the 11 stage CW SHOULD HAVE BEEN ENOUGH to generate only negative ions
250VACx1,4141x11=3888.775 VDC
...
Even with a 12 stage the voltage should be "betwen limits" and not generate ozone!
I'll see how the air becomes in the room in wich I have the CW left operating for some time now...
I'm preety dissapointed regarding this voltage multiplier!
I mean , OK , it multiplies the voltage from the mains , but does it really generates negative ions?
From one thing to another I'll probably have to make and an negative ion "tracker"/detector :roll:
who knows more is welcomed to add his/her's ideeas...
:shock:

 

[FvM]

The curent should be 30 microamps per needle!
I intend to use 36 needles so I guess the curent would be 1,08 miliamps...

That's definitely impossible with the present dimensioning. The circuit presented in your post #3 is designed for a current several orders of magnitude below it and you never mentioned a different specification.

See a LTSpice simulation circuit in the attachment to test the effect of the cascade rectifier capacitance.

 

[leaualorin]

That's definitely impossible with the present dimensioning. The circuit presented in your post #3 is designed for a current several orders of magnitude below it and you never mentioned a different specification.

See a LTSpice simulation circuit in the attachment to test the effect of the cascade rectifier capacitance.

I didn't made that one!
I just made a classic 12 stage CW(listened to your advice) with 100nF/400VAC poliester capacitors and 1N4007!
When mentioning 30 microamps I was thinking about the specifications from the US PATENT 4816684 ...
Sorry for missleading , I got all too "excited" about this negative ions "thing" and since I'm "tinkering around it" since morning thoughts sometimes can come out "unfiltered"!
:-D

I have no ideea of what the curent would be for the galvanized tin with 36 needles on it...
COULDN'T BE MORE THAN THE 1N4007 1 AMP RATING...
FvM , you "got me confused" here with the simulation...
I'm using Fedora 15 and after "extraction" it showed me a bunch of numbers and data...

 

[FvM]

COULDN'T BE MORE THAN THE 1N4007 1 AMP RATING...

The 100 nF capacitor will safely prevent ...

Honestly, I have no idea of the field emission current amount. It has to be measured.

The LTSpice simuation circuit is provided for convenience, it's a LTSpice specific ASCII schematic format, operational with the free simulator. If you are using a different tool, you'll surely know how to setup a cicruit yourself. It's however helpful to understand the current source capabilities of the cascade rectifier.

 

[leaualorin]

FvM , forget about curent :roll:
I had some bussines to solve and left home for 2-3 hours WITH the ioniser on , and 3 simple paper pins soldered on a copper wire ,soldered on the final HV capacitor end!
Before this I burned 2 incent sticks to see how well will the ioniser get rid of the smell and how fast!
I was amazed to see that after 2-3 hours the room in wich it had sat didn't even had a trace of incent smell!
AMAZING INDEED!
In fact , the air was really fresh!(nose "analyzer :-D ).
I don't think I'll use anymore galvanized tin or copper sheet , but instead build the "pin farm" out of simple ordinary pins that are about 25mm long soldered on copper wire somewhat shaped to have o hole in wich to put and solder the pins!
The same goes for the "earth/zero potential"/ neutral circular part of the electron optics wich should improve the negative ions emission!
I also found some 5 Mohm resistors but they are rated 10watt each...
Because I don't have from were to choose I'll try and mount those!
Is it REALLY "BAD" if I install only two 5Mohm resistors ?
I understand that these resistors limit the current wich would pass through the system should some STUPID HUMAN( I'll write BIG and clearly "DO NOT TOUCH" on the ioniser), would touch the pins but at 10Mohm there's any danger of death?
I mean , how the heck do I calculate the current that MIGHT pass into the STUPID HUMAN that might touch the pins with a 10Mohm resistor at the HV end?
I don't want to have a "quilty conscience" !
Overall , "I THINK" I changed my mind regarding the ioniser; it's a very usefull thing for any home , IT REALLY WORKS in removing dust, odors , it makes a very good smelling , breathable air wich makes a difference on these hot days!
But very much attention must be given to the electricall isolation of the system so that it works at full potential!
I learned this after trying more versions of the electron optics!
Right now it works even faster in freshning the air with a 19 pins soldered on copper wire!
I'll work more and finish the "thing" maybe even configure the electron optics as it is shown on the US patent 4816684 with the neutral wire around the pins for better negative ions emission!
Right now I have to take a GOOD break , eat something , shower , etc...
:grin:
Good day to all !
Gabriel!