# Anyone know of a place that sells 10 farad capacitors rated at 20k volts

1. May 16, 2006

### Agnostic

Anyone know of a place that sells 10 farad capacitors rated at 20k volts

2. May 17, 2006

### NateTG

No, that's on the scale of large reserach facility capacitor banks.

3. May 17, 2006

### Staff: Mentor

What'cha makin'?

4. May 17, 2006

### Hammie

Maybe an inter-galactic bug zapper?

5. May 17, 2006

### Hammie

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 [Broken]

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,

Last edited by a moderator: May 2, 2017
6. May 17, 2006

### Agnostic

Looks like an interesting place considering the bombing of Dresden :)...So it goes

7. May 17, 2006

### Agnostic

I am doing some undergraduate research....

I guess the capacitance isnt difficult, but the voltage is...

8. May 17, 2006

### Agnostic

Maybe I am being a little overzealous....

9. May 17, 2006

### Staff: Mentor

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

DryQ DC
http://www.abb.com/global/seitp/seitp332.nsf/0/7fce68898da2ef14c1256f64005041b0?OpenDocument [Broken]

Siemens
http://www.epcos.de/web/generator/W...tronics/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. :uhh:

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.

Last edited by a moderator: May 2, 2017
10. May 18, 2006

### Hammie

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.

:surprised

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..

Last edited: May 18, 2006
11. May 18, 2006

### Agnostic

I just realized a typo...I meant 10 microfarad...

12. May 18, 2006

### NateTG

13. May 19, 2006

### Hammie

Be careful with the surplus stuff. Some of the really old oil filled units contain PCB's.

14. May 19, 2006

### Staff: Mentor

Makes a big difference.

There are plenty of suppliers for 20 kV, 10 $\mu$F capacitors.

For example - http://www.hivoltcapacitors.com/page1.html [Broken]

http://www.morganelectroceramics.com/capacitors/index.html [Broken]

ABB, Siemens woud also supply such capacitors.

See http://www.lambda-emi.com/product_html/203power.htm for charging systems.

Last edited by a moderator: May 2, 2017
15. May 19, 2006

### turbo

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. :rofl:

16. May 19, 2006

### enigma

Staff Emeritus
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 realise how dangerous they can be.

17. May 20, 2006

### Staff: Mentor

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!

18. May 20, 2006

### x64bob

lol that would totaly own