Instructables

I was given a 42uF 12KV oil capacitor. Any suggestions for having some high tech fun with it?

It's rated for oscillatory currents, pretty old, but it is in good cond. electrically. I can easily and safely charge and discharge it. The thing is, it was free, and I suppose I couldn't turn it down. Now what? The highest voltage I would possibly need a filter cap for is 4500 for an amplifier, so that's out. The "oscillatory currents" rating makes me think it was for energy storage and high frequencies. It is likely from LANL surplus.

Can crusher? disc launcher? I'm mainly interested in suggestions for projects that will focus on a fast discharge and high peak power levels, and do not require a lot of additional items, but I am open to any decent ideas.

Yeah, the "fast discharge" part is kinda tricky.  One way to do this is using some sort of triggered spark gap.  Such devices are probably the best DIY way to go.  I was trying to find some pictures, but the search results have been kind of disappointing.  People call them by different names, "spark gap switch", "triggered spark gap", "trigatron", etc.

http://en.wikipedia.org/wiki/Trigatron
http://en.wikipedia.org/wiki/Pulsed_power
http://www.angelfire.com/80s/sixmhz/trigatron.html

Somewhere around here, I've got book containing a better picture of such a device.
Also:  Pulse Power Switching Devices - An Overview By John Pasley 24/9/96
http://www.electricstuff.co.uk/pulse.html
I've attached some pictures from that book:

Iannini, Robert E.  Build Your Own Laser, Phaser, Ion Ray Gun & Other Working Space-age Projects. Tab Books. 1983
http://books.google.com/url?id=LwQqKAAACAAJ

Specifically these are pages 228 and 229, from project #15, titled  "High Energy Pulsed Source"

There may be something significant about the use of spheres for the main electrodes.  I am guessing smooth surfaces are used for the main electrodes to prevent spontaneous discharge.   BTW, the capacitor bank used for this project was about 500 uF at a maximum voltage of about 1800 V = 1.8 KV

The picture of the cover is included because I think the cover art is pretty, and also it has kewl robots on it.
;-)
pulsed_power-iannini-p229-gray.jpgpulsed_power-iannini-p228-gray.jpgiannini-byolaser-1983-cover.jpg
Opcom (author) 4 years ago
There is a picture of it here: http://www.bunkerofdoom.com/travel/nm2010/capacitor.jpg - showing the ratings. It's not the largest one I have ever seen but it is the largest one I have ever had. The history of it is that it was ordered from GE by the person doing the hydroforming work using an underwater triggered spark gap and this type is was what was recommended by GE for this straight discharge duty at the time.
Opcom (author) 4 years ago
It was difficult to pick the best answer between Jack A Lopez and rickharris. Ultimately Jack gave the most helpful answer by suggesting a dischrge scheme. However, the hazard associated with PCB as stated by rickharris cannot be overlooked. A wise person pays attention to oil filled electronic devices to see that they are not leaking and when they are leaking, even seeping, it is time for proper disposal.
Opcom (author) 4 years ago
First, thanks for all the good answers. I am grateful for the information. -- Second, I apologize as there is some issue between my computer and instructables. it is ignoring my formatting and refuses to display my image upload of the capacitor nameplate. ==== Oh well here we go: --- #1 I am aware of the pyranol, and will dispose properly when the time comes. Also aware of the hazards. I work with only 3000-5000V @ 1A, and so 12KV on a 43uF cap is another matter. #2 i do have a HVPS to charge it with. 0-15KV @ 100mA. So here is the data: ----- The nameplate says: --- high current ocillatory discharge device ---- ringing freq 1500 Hz ----- reversal 65% ----- expected life 5000 disch. ----- electrification 1000 hours. ==== so, those are the specs right off the can. It is about 28" tall, 18 " wide, and 6" thick. 60-70 lbs. one terminal is grounded to can. I will contact GE and ask them . Who knows, there might be a drawing for it somewhere. ----- If the data here is useful, I would be grateful for further information.
rickharris4 years ago
Depending on it's age it may well be filled with PCB  if so it is highly toxic and would need to be disposed of at a certified facility (that may be why you got it free!!)

As a radar engineer in the 60s and 70s we used such capacitors as pulse forming networks. Charged to any amount they are potentially deadly - remember that as little as 50 volts and 30 milli amps can kill you under the right conditions.

As with any capacitor age weakens them so I wouldn't recommend anything other than correct disposal.  DONT bury it as it will eventually leak and the PCB may get into your water supply.
lemonie4 years ago
It may be of use in a high-voltage generator, but 42uf is very little capacity.
Have got any high-voltage equipment?

L
42 uF is kinda big for a capacitor rated at that voltage.  I mean fully charged it's like 3 KJ.  (since 0.5*(42e-6)*(12e3^2) =  3024)
If the dude has a HV charger. (Which is why I asked)

L
Don't know what its from, but just because its a high voltage doesn't mean its a fast discharge rated one, so more research may be needed as to what its for.

What it WOULD do is kill you stone dead.....