- #1
Agnostic
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Anyone know of a place that sells 10 farad capacitors rated at 20k volts
Anyone know of a place that sells 10 farad capacitors rated at 20k volts
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Discussion Overview
The discussion revolves around the availability of 10 farad capacitors rated at 20k volts, exploring potential suppliers and the implications of such components in various applications. The conversation includes technical considerations, safety concerns, and speculative uses for high-capacity capacitors.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Conceptual clarification
Main Points Raised
- Some participants express skepticism about the feasibility of obtaining 10 farad capacitors at 20k volts, suggesting they are typically used in large research facilities.
- One participant humorously speculates about the application, suggesting it could be for an "inter-galactic bug zapper."
- A participant calculates the energy storage capacity required for such a capacitor, indicating it would be around 2 GJ, and notes that this is a significant amount of energy.
- Some participants mention that while 10+ microfarad capacitors at 20k volts are available, a 10 F capacitor would be more suited for power transmission systems.
- References to specific companies like ABB and Siemens are made, with links provided to their capacitor products, although it is noted that the largest capacitors from Siemens are only 16 milli-F.
- Concerns are raised about the safety and practicality of charging such a large capacitor, with one participant humorously estimating the time it would take to charge it using a typical television power supply.
- Several participants clarify that the original request was likely a typo, intending to ask for 10 microfarads instead of 10 farads, which significantly changes the context of the discussion.
- Warnings are issued regarding surplus capacitors, particularly older oil-filled units that may contain hazardous materials like PCBs.
- Speculative comments about the potential for dangerous applications, such as an EMP device, are made in jest, reflecting the participants' concerns about the implications of high-energy capacitors.
Areas of Agreement / Disagreement
Participants generally agree that a 10 farad capacitor at 20k volts is unusual and likely impractical for typical applications. However, there is no consensus on the exact nature of the original request, as it is revealed to be a likely typo for 10 microfarads, leading to differing views on availability and application.
Contextual Notes
Some participants express uncertainty about the safety and practicality of using such high-capacity capacitors, particularly in undergraduate research settings. The discussion highlights the potential dangers associated with large energy storage and the implications of using such components.
- #2
NateTG
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Agnostic said:
No, that's on the scale of large reserach facility capacitor banks.
- #3
berkeman
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What'cha makin'?Agnostic said:
- #4
Hammie
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Maybe an inter-galactic bug zapper?
- #5
Hammie
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I think I found one for you, kind of. It is just a tad small though.
http://www.rheinmetall.de/index.php?fid=1805&lang=3
Using J = 1/2 C E^2, you are asking for a 2 x 10^9 Joule capacitor. This one is only 5 x 10^7,
About forty of these should make it about right..
http://www.rheinmetall.de/index.php?fid=1805&lang=3
Using J = 1/2 C E^2, you are asking for a 2 x 10^9 Joule capacitor. This one is only 5 x 10^7,
About forty of these should make it about right..
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- #6
Agnostic
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Looks like an interesting place considering the bombing of Dresden :)...So it goes
- #7
Agnostic
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I am doing some undergraduate research...
I guess the capacitance isn't difficult, but the voltage is...
I guess the capacitance isn't difficult, but the voltage is...
- #8
Agnostic
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Maybe I am being a little overzealous...
- #9
Astronuc
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There are plenty of 10+ microF capacitors around for voltages of 20 kV, however, a 10 F capacitor at 20 kV would be for a power transmission system.
ABB or a power electronics company would probably have those.
20 kV is considered medium voltage which would be used in local distribution systems.
ABB HiQ - Capacitor Units (Power Capacitors)
The first application for DryQ capacitors is shunt banks rated for 40–170 kV and 10-100 MVAr.
DryQ AC
http://www.abb.com/global/gad/gad02077.nsf/lupLongContent/DD6C0BD19EACD8FCC1256FA30054CAC2
DryQ DC
http://www.abb.com/global/seitp/seitp332.nsf/0/7fce68898da2ef14c1256f64005041b0?OpenDocument
Siemens
http://www.epcos.de/web/generator/Web/Sections/ProductCatalog/Capacitors/PowerCapacitors/CapacitorsForPowerElectronics/Page,templateId=render,locale=en.html
Siemens largest capacitor is 16 milli-F.
10 F seems a bit large.
I know one place that used huge inductors for energy storage and they had to use explosive switching. They were doing 10+ kA.
I had the same thought as berkeman - that's a mighty big charge one is contemplating.
And as Hammie pointed out, 2 GJ is a rather large energy storage. That's the output of typical 1000 MWe in 2 seconds. I can't imagine an undergrad doing research with such an amount of stored energy. One can explode wires with that energy/power.
ABB or a power electronics company would probably have those.
20 kV is considered medium voltage which would be used in local distribution systems.
ABB HiQ - Capacitor Units (Power Capacitors)
The first application for DryQ capacitors is shunt banks rated for 40–170 kV and 10-100 MVAr.
DryQ AC
http://www.abb.com/global/gad/gad02077.nsf/lupLongContent/DD6C0BD19EACD8FCC1256FA30054CAC2
DryQ DC
http://www.abb.com/global/seitp/seitp332.nsf/0/7fce68898da2ef14c1256f64005041b0?OpenDocument
Siemens
http://www.epcos.de/web/generator/Web/Sections/ProductCatalog/Capacitors/PowerCapacitors/CapacitorsForPowerElectronics/Page,templateId=render,locale=en.html
Siemens largest capacitor is 16 milli-F.
10 F seems a bit large.
I know one place that used huge inductors for energy storage and they had to use explosive switching. They were doing 10+ kA.
I had the same thought as berkeman - that's a mighty big charge one is contemplating.
And as Hammie pointed out, 2 GJ is a rather large energy storage. That's the output of typical 1000 MWe in 2 seconds. I can't imagine an undergrad doing research with such an amount of stored energy. One can explode wires with that energy/power.
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- #10
Hammie
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Another thought, or two..
How do you plan on charging this little bugger?
I figured that, using the 20KV anode supply for a 13 inch television, you'd be safe limiting the current such that the source is supplying about a maximum of 10 watts or so.
The series resistor would have to be about forty megohms give or take.
It takes about five time constants to charge it to 99 % of the source voltage.
One time constant is 4 x 10^8 seconds. That is rougly thirteen years, to charge it to only 63 percent of 20KV.
As funny as all this may sound, it does give me an appreciation for what they are doing with those huge capacitor banks..
I don't think I could afford the electric bill for even one charge cycle.
1/2 amp to the TV, the bill would be about a million and a half, at today's rate of about five cents per kilowatt hour.
I'm only forty nine now. I think I'll pay at the end of the charge period..
edit:
I redid the figures.. only $333.33 dollars to do one fifth the job.. I never was good with finances..
How do you plan on charging this little bugger?
I figured that, using the 20KV anode supply for a 13 inch television, you'd be safe limiting the current such that the source is supplying about a maximum of 10 watts or so.
The series resistor would have to be about forty megohms give or take.
It takes about five time constants to charge it to 99 % of the source voltage.
One time constant is 4 x 10^8 seconds. That is rougly thirteen years, to charge it to only 63 percent of 20KV.
As funny as all this may sound, it does give me an appreciation for what they are doing with those huge capacitor banks..
I don't think I could afford the electric bill for even one charge cycle.
1/2 amp to the TV, the bill would be about a million and a half, at today's rate of about five cents per kilowatt hour.
I'm only forty nine now. I think I'll pay at the end of the charge period..
edit:
I redid the figures.. only $333.33 dollars to do one fifth the job.. I never was good with finances..
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- #11
Agnostic
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I just realized a typo...I meant 10 microfarad...
- #12
NateTG
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Agnostic said:
Ah. Only a factor of a 1,000,000.
A friend of mine was selling something close to that surplus:
http://theelectrostore.com/shopsite_sc/store/html/capacitors.html
Which obviously suggests checking out:
http://www.maxwell.com/
- #13
Hammie
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Be careful with the surplus stuff. Some of the really old oil filled units contain PCB's.
- #14
Astronuc
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Agnostic said:
Makes a big difference.
There are plenty of suppliers for 20 kV, 10 [itex]\mu[/itex]F capacitors.
Just use Google, "Capacitor","20 kV"
For example - http://www.hivoltcapacitors.com/page1.html
http://www.morganelectroceramics.com/capacitors/index.html
ABB, Siemens woud also supply such capacitors.
See http://www.lambda-emi.com/product_html/203power.htm for charging systems.
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- #15
turbo
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Now you know why people were curious about the application. I figured you were going to build an EMP device big enough to knock out the northeast.Agnostic said:
- #16
enigma
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Aye. I saw 10F before I read down further and all I saw was the robot from the Space Family Robinson:
DANGER DANGER
I get REALLY nervous around the 500mF caps we have in the lab because there are some people there who don't realize how dangerous they can be.
- #17
Astronuc
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Putting this in perspective -
2 GJ is the kinetic energy of 1 kg traveling at a speed of 63.245 km/s or 10 kg traveling at 20 km/sec.
A 100 kg man would have that amount of kinetic energy at 6.325 km/s and that is pretty darn fast!
2 GJ is the kinetic energy of 1 kg traveling at a speed of 63.245 km/s or 10 kg traveling at 20 km/sec.
A 100 kg man would have that amount of kinetic energy at 6.325 km/s and that is pretty darn fast!
- #18
x64bob
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lol that would totally ownturbo-1 said:Now you know why people were curious about the application. I figured you were going to build an EMP device big enough to knock out the northeast.