Precipitator power supplies?

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ian_krase
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Precipitator power supplies?

Post by ian_krase »

One type of power supply (either of the "hurts if you drop on foot" or "burns out semiconductors" type) that I haven't seen discussed here very much is a precipitator supply. As far as my research can tell, these devices need to maintain fusion levels of voltage (>40 kv seems common) while having fusion levels of current leaking into the dusty air due to Corona and huge plates.

And I found one for a *very* good price. It looks nearly identical to the one in this thread: ?f=6&t=9355&p=63246&hilit=Precipitator with an array of flybackish-looking transformers. However, I don't know if that guy was able to actually provide fusion levels of power. The one I found is rated at IIRC 450 watts


Is this a viable or nearly viable supply type, or is it another short-circuit-current/open-circuit-voltage/peak-pulse-power dodge?
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Re: Precipitator power supplies?

Post by Jerry Biehler »

I have worked on pretty big units in machine shops and the power supplies will supply no where the current needed for a fusor. Plus they have arc detection that shuts down the power supply when it sensed abnormal loads.

Precipitators are designed not to have corona, that causes ozone and nitrous oxide which is bad.
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Re: Precipitator power supplies?

Post by ian_krase »

Huh. I'm not terribly surprised. What justifies the huge current ratings, then?
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Re: Precipitator power supplies?

Post by Jerry Biehler »

Larger one for industrial units might work. I really am not sure. I just wouldn't expect much from a cheap chinese power supply.
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Re: Precipitator power supplies?

Post by ian_krase »

Ok, OK, I'll break the secrecy. It is indeed cheap and Chinese, but it appears to be small quantity surplus, not something being sold at normal market value. So I don't really know. The claimed capabilities are pretty significant, but I can easily understand it not living up to them.

Could be interesting even if it only provides a fraction of the current.

It's this one: http://www.ebay.com/itm/High-voltage-el ... SwY3BZGnHF
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Re: Precipitator power supplies?

Post by John Futter »

Ian
yes you should have posted this at the beginning
yes that is capable of a least 460 watts if not a lot more.
It looks so simple that i doubt that it has current limit but a good series resistor appropriatly sized will protect the supply.
you could get more control by feeding it with a voltage current limited DC 200 -350volt supply
those flybacks are good to about 150 watts each --depends on caps an diodes on the output as these will be the limiting factor
Be cyee warned these are meant to swing about earth ie you will have -30kV 0 +30kV although there is no apparent earth connection.
earthing one side might strain the creepage on the pcb and transformer winding to core with little attention being paid to corona possibilty
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Re: Precipitator power supplies?

Post by ian_krase »

So you say that it has a center tapped DC output? Huh. Could be useful for some types of accellerator....
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Re: Precipitator power supplies?

Post by John Futter »

ian
Read again
No I did not say it had a centre tap
but it is designed to swing about earth albeit earth being phantom
+- 30kV is very different from 0 60kV for the reasons in my earlier post
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Re: Precipitator power supplies?

Post by ian_krase »

Oh, I get it.

Maybe needs the mineral oil / paraffin / whatever treatment?
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Dennis P Brown
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Re: Precipitator power supplies?

Post by Dennis P Brown »

I am concerned that the voltage swings which means the average power (in the very high range say 25- 30 kV) is going to be low and not what you see as the input power for the main supply. I seriously doubt the unit will be good for a first time user; I would speculate that this is rather an interesting experiment for someone that has a proven detector (i.e. known calibration and/or noise level for a given neutron count) and has created neutrons in a proven machine. Yes, the price is acceptable as long as one doesn't mine it not creating neutrons ... . By the way, if it did only produce a fraction of the current (as you suggest) than 460 watts quickly falls below the required threshold for a viable fusor - yes, a good/outstanding detector can partly make up for lower current but again, not a good way for someone with a new fusor and no neutron experience.
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Re: Precipitator power supplies?

Post by ian_krase »

You're saying that to use this in a (conventional) fusor one would ground the, well, ground, and then use the negative 30kv output to drive the grid (And yes, that does sound rather low, and low current to boot)

Is that correct?

This suggests that an unconventional system (i.e. one with different grounding requirements) might use both ends properly?
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Dennis P Brown
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Re: Precipitator power supplies?

Post by Dennis P Brown »

To use this power supply for a real fusor one needs a couple of things (previously mentioned in this thread.) First, one MUST get a negative output from this wildly swinging AC source so diodes (at least two but a bridge could also be done) are required; and second, a ballast resistor to prevent a massive over current flow when a plasma first ignites. The resistor issue is well covered in the FAQ's on power supplies. Of course, the diode as you may or may not know is seeing a higher peak voltage than the max rated voltage for the supply (for any AC powered device) so these diodes must be rated for the higher voltage with some safety factor. As for grounding, that is an issue but that depends on the supply - the fusor's chamber itself (generally) is the main ground. Grounding a flyback isn't a straight forward thing to do. Yes, the case should be grounded but most flybacks I've seen (not too many, however) float. Other's can weigh in on that specific topic.

Aside: don't underestimate the lethality of flybacks - even if the unit can't do fusion that PS will be deadly with anywhere near that power. Use proper cables and follow all standard HV safety protocols.
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Re: Precipitator power supplies?

Post by Jerry Biehler »

Wildly swinging AC source? This unit should be DC out. Precipitators dont work on AC. The negative size goes to the wires in the collector and positive to the plates where the particles are collected.

Those transformers probably have diodes built in.
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Re: Precipitator power supplies?

Post by John Futter »

Ian
No you would connect the positive output to ground and the negative output to your grid, but because of what i said earlier this may compromise
creepage distance on the PCB and the flyback transformers winding to core
they certainly dont cost much so it is worth a try
Shireesh Apte
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Re: Precipitator power supplies?

Post by Shireesh Apte »

This is the high voltage unit I have recently used to generate a plasma at 100 microns pressure. If the specs are to be believed, this unit may be capable of (mid-range) 30 KV and 10 mA. By all accounts, from whatever I have read on the FAQ posts, this should be good enough to detect fusion. By the way, my plan is to use a silver sample contained in a moderator (i.e a water bath) so as to allow the (slower thermal neutrons) to convert part of the silver to cadmium and emit gamma and x rays that I can detect with a Geiger counter.
I will of course devise methods to measure the actual voltage and current for the fusor part of my project.
Thanks and Best regards,
Shireesh Apte
electrostaticprecipitator.jpg
High Voltage Electrostatic Precipitator Power Supply with 400W 60kV

Specifications

1.Input voltage AC160V-260V

2.The output voltage is DC5KV-60KV, adjustable speed

3.Output current 8-12mA

4.Size: 230*180*80mm

5.Weight 1.78KG
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Finn Hammer
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Re: Precipitator power supplies?

Post by Finn Hammer »

Gods speed to you, for testing this supply.
Those of us who has had access to better supplies like Spellman et al will tend to disbelieve the suitability of it, with regard to delivering, in particular, the voltage. I doubt it too, due to experience with similar supplies, where corona issues, and tracking, put an end to the transformers. But this is speculation, whereas nothing beats hands on experience, and you are getting it.
Looking forward to read your results.
Cheers, Finn Hammer
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Richard Hull
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Re: Precipitator power supplies?

Post by Richard Hull »

Those flybacks look like the type with diodes in them. If those are repurposed TV flybacks, the voltage out is positive. I suppose a manufacturer might have special negative polarity diodes potted into them. Like Finn, I hope you efforts pay off. Keep us in the loop and report your efforts as they go.

Richard Hull
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Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Shireesh Apte
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Re: Precipitator power supplies?

Post by Shireesh Apte »

Thanks Finn, Richard,

My students rigged the potentiometer knobs with a short piece of tubing into which glass rods were inserted (attached). These glass rods project out of two holes in a wooden enclosure made from waste oriented strand board that I scavenged from Lowes. I will post a photograph next week. I am a novice at circuits (as with almost everything else - as I have found that Knowledge is essentially a black hole) but so far- my method has been NOT to touch ANYTHING once I have it fired up. I am learning as I go - I realize this is dangerous; but as the man said - D-day might have been under entirely different circumstances had Eisenhower waited for the weather to clear.
The safety of my students is my primary concern and I take that very seriously - even with the more zealous (Instant gratification) types - as I seem to have this year helping me on my 'Star-in-a-jar' and 'fusor' project.
I will post detailed pictures of my set up in the 'construction' part of the forums next week.
By the way, my expertise (such as it is) lies in the field of Pharmaceutical excipients -having worked for over 20 years in the pharmaceutical industry - and you can find many of my manuscripts in the peer-reviewed journal I run: https://jefc.scholasticahq.com
Thanks again.
Best,
Shireesh
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Dennis P Brown
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Re: Precipitator power supplies?

Post by Dennis P Brown »

I have my doubts that 30 kV at 10 ma is enough to activate Ag that is detectable (if that supply really is providing enough average power to really provide a full 300 watts - as I said previously, being an AC driven system (the flyback), the output current is varying a great deal so the real average power could be less than that simple calculation would lead one to believe.) That said, since you came this far, might as well try it. However, if you are unable to detect activation of Ag, that does not necessarily mean you've had no fusion (if your real power is three hundred watts you likely have some not insignificant level of fusion.) So, don't be discouraged. Detecting neutrons is not easy.

I say this because I can easily detect fusion neutrons using my Russian boron-based gas filled tube and my fusor power is 1500 watts (or more) but I can't activate Ag enough to detect it using a Geiger tube. That could, partly be geometry issues but still, in the FAQ's, three hundred watts is not considered enough to activate Ag, if memory serves.

That all said, how are you going to measure both the voltage and current of that power supply? Knowing those values is essential to determining if the supply is even capable of being used for fusion and is delivering those values to the plasma. I ask this because determining that this flyback based supply can deliver that level of power would be a very useful contribution to this forum.

I may have forgotten if you already talked about this topic but what type of chamber are you planning to use? Saying "star in a jar" is not reassuring ... if you get my drift.

Finally, I know only what you posted and what the picture shows about that power supply - the two input points (if they are) then require a single phase source, which means you need 208 AC single phase - that is not routinely available. Three phase 220 does not appear to be supported by that supply - hopefully, that isn't the case. But since you indicate you know little about electricity, that is a rather critical issue if you plan to power that specific supply (single phase 120, if the documentation is correct, will not be sufficient.) Maybe check the instructions and confirm that input issue.
Last edited by Dennis P Brown on Mon Oct 30, 2017 7:02 am, edited 2 times in total.
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Finn Hammer
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Re: Precipitator power supplies?

Post by Finn Hammer »

Shireesh,

For your consideration, here is an image of the voltage divider I use for my high voltage work. It is shown hooked up to another Precipitator supply that I am evaluating for a precipitator project I am associated to.
It is a 20.000 : 1 divider. The high voltage resistors are 1% 20Mohms, 10 of them, the bottom resistor is 10Kohm.
The resistors are terminated in 6mm brass balls, and there are potential rings at the top. I should have completed the rings all the way down, but got distracted.
It is fine for DC work, but lacks compensation for AC work, where a sophisticated arrangement of parallel capacitors would be needed.
Feel free to replicate, It will serve you well.
IMG_20171030_113626.jpg
Hope this helps

Cheers, Finn Hammer
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Re: Precipitator power supplies?

Post by Shireesh Apte »

Thanks Dennis, Finn,

Yes, the precipitator does take a 220 V input. I have a voltage converter attached to the Variac into which I plug in the precipitator input (see pictures). I will research the silver to cadmium transition further as regards the minimum detection threshold. Thanks Dennis for posting your measurement apparatus. I will research this further.
20171030_081230.jpg
20171030_081156.jpg
20171030_081041.jpg
20171030_081029.jpg
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Re: Precipitator power supplies?

Post by Silviu Tamasdan »

Um that up-converter is rated for 50W.
Based on some previous experience I sincerely doubt it's even able to sustain that for more than a few minutes at a time.
It's extremely under-powered for your purpose.

Remember, the strength of a chain is not greater than the strength of its weakest link.
There _is_ madness to my method.
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Dennis P Brown
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Re: Precipitator power supplies?

Post by Dennis P Brown »

Silviu Tamasdan is correct; your output will be 300 watts (assuming 30 kV @ 10 ma), so the input power must exceed that by a good bit, too. Power out can never be greater than power in ...that is, unless one has achieved economical fusion ...sorry, had to get that last part in.

Your approach makes excellent sense to test the device's operation but you must keep the current drawn by the HV system very low so as not to blow that step up converter. So a powerful and sufficient ballast resistor is essential before hooking this power supply up to create a plasma. That should allow you to test the device at 1 or up to 1.5 ma. If you get close/hit 2 ma, that will exceed that voltage convert's limits. Remember - the power rating of a device is an absolute limit that rarely can hold up long.

Along these lines, a measurement of the input power (easy - any voltmeter and a decent amp gauge can handle) will tell you a lot. If the HV system is running all out and the input voltage/current are under 200 watts, the supply will never do detectable fusion (say, 200 volts in, @ 10 amps to that HV system equals 200 watts going in and that means you are not getting even 200 watts out (remember, voltage devices never convert perfectly; they always suffer power losses.)

It appears from the pic that all the flyback's are wired such that there is a single main "output" wire? The red one (and the black is, ground)? How do the other flyback's connect together via that single output? Maybe a lower board picture will clarify that issue for me.

Again, your making progress but there will often be issues that create problems that prevent getting to where one thought ...I have learned this all too often in getting my fusor to work (lol.) Keep at it. You have gotten along very well considering your starting point.

AS I tell new people here all the time - be very careful with high voltage power systems! You get no second chances so they must be as fool proof as possible. One time not thinking and if the supply is lethal, then that person is dead. Be safe and exercise caution: especially if anyone else is around who does not understand the danger. Never allow anyone to interact or run a deadly high voltage system that isn't fully knowledgeable of the dangers and knows how to be safe around these potentially lethal systems.

This brings us to x-rays; a 30 kV, 10 ma source can be a significant x-ray hazard. One cannot expose either one's self (if one is sane) and most certainly not innocent bystanders to dangerous levels of radiation. So, that is a safety issue you must address now before you operate that power supply in a manner that can create x-rays - maybe it will turn out that the supply is too weak to be a danger but if it does put out a few milliamps in the 20+kV range, it is a radiation hazard when used in a fusor arrangement and you MUST follow all local laws/regulations for radiation since you are operating this in a public institution.
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Re: Precipitator power supplies?

Post by Richard Hull »

The last part of Dennis' post regarding radiation should send one screaming to the FAQs in the Radiation forum. Read and learn.

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Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Precipitator power supplies?

Post by Silviu Tamasdan »

Just as a side note, it seems to me that the way those flyback transformers are used is inefficient. Guess it's because they used off-the-shelf parts. I've been doing some calculations lately related to my own power supply woes (no way to find an adequate high voltage transformer so I'm designing my own high-frequence power supply with ferrite core). The power supported by a ferrite core increases with the square of the core area. Having 4 discrete transformers each with its own secondary winding in parallel is less efficient (at least for cores over a certain size) than sticking the cores together and winding one secondary over all of them.
(In my case I'm looking at some cores with an area of 16cm2; each core would support transfer of around 180W, but 3 stuck together to form one core with the area of 48cm2 they would support over 1.5kW)
There _is_ madness to my method.
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