Precipitator power supplies?

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Shireesh Apte
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Re: Precipitator power supplies?

Post by Shireesh Apte » Mon Oct 30, 2017 2:59 pm

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.
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Silviu Tamasdan
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Re: Precipitator power supplies?

Post by Silviu Tamasdan » Mon Oct 30, 2017 4:38 pm

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 » Mon Oct 30, 2017 5:11 pm

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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Richard Hull
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Re: Precipitator power supplies?

Post by Richard Hull » Tue Oct 31, 2017 5:54 am

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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Re: Precipitator power supplies?

Post by Silviu Tamasdan » Wed Nov 01, 2017 1:22 pm

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)
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Re: Precipitator power supplies?

Post by Shireesh Apte » Wed Nov 01, 2017 4:30 pm

Thanks Silviu, Dennis

The 50 Watts was enough to generate plasma. It will obviously not do fusion. Having obtained a plasma (and hence some funding - which I desperately need) based on proof-of-concept, I can now turn my attention toward fusion proper. Before I abandon the electroprecipitator, I will measure the output once I have the requisite input device. I am less concerned with how efficient (or inefficient) the transformers themselves are so long as they output the required volts and amperes needed (considering that my end result -fusion - is itself extremely inefficient with this experimental setup).

I will post all the hardware I have acquired in the 'construction' part of the posts.

By the way, I aim to find out to what vacuum I can reach with my plasma supplies and two rotary vane pumps 1]connected in series and 2] connected in parallel. I know there is a probably a lot of literature that already exists on this. However, since I have the supplies and it is an easy enough experiment; at a minimum; it will be experience gained.
Best,
Shireesh

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Re: Precipitator power supplies?

Post by Silviu Tamasdan » Wed Nov 01, 2017 6:09 pm

With rotary vane pumps connected in parallel, I don't think you will see a higher vacuum than with one pump, but you will probably achieve that vacuum faster. With pumps in series, I think that you will have issues with oil from the first pump being sucked into the second one. These usually aren't designed to have anything connected after them.
There _is_ madness to my method.

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Re: Precipitator power supplies?

Post by ian_krase » Wed Nov 01, 2017 7:28 pm

Don't connect rotary vane pumps in series. Bad idea.


There's a kind of mechanical pump meant to go in series with a rotary vane pump, called a Roots Blower, but you probably don't need one and they are usually huge industrial devices any way.

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Dennis P Brown
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Re: Precipitator power supplies?

Post by Dennis P Brown » Thu Nov 02, 2017 9:10 am

Agreed that series with your pumps isn't a good idea; parallel, while it will make things a bit faster that arrangement will not get a system any lower. If the pumps can't get down below 50 microns (the least for a DP to operate in a fairly safe manner), then they simply aren't sufficient for the job; however, I still believe your pumps aren't the issue but the connectors you use for both the pumps and that vacuum gauge (with its highly questionable connector methodology.) Get a micron gauge that uses standard vacuum connectors - KF stuff isn't expensive if one looks carefully on ebay and explores what surplus companies offer. One can get absolute steals if one is careful.

No fusor project can get off the ground until a viable vacuum system exists - period. Focus on that; otherwise, you are wasting resources.

For instance - you need to convert your vacuum pump to some type of KF fitting. Here is a possible fitting type for your pump:

https://www.ebay.com/itm/1-4-Male-BSPT- ... SwPDZZdDK-

This is a new adapter and very low cost; yes, you will then need a TC gauge (or similar) with a matching KF fitting but that is how one starts to build a leak proof, usable fusor vacuum system. Think this out before buying more power supply's, or a DP or deuterium gas.

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Re: Precipitator power supplies?

Post by Jerry Biehler » Thu Nov 02, 2017 10:14 pm

People have connected rotary pumps in series, you can get a lower vacuum. How much, who knows. You wont hurt anything.

Parallel will get better throughput.

Just get a good vacuum pump to start with. I have a friend that is selling a whole bunch of nice adxien (alcatel) pumps. Not cheap, but a good price.

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