Wanted: Capacitors

Don't think you will find an odd size like that. Caps are usually low tolerance in standard sizes.. which don't extend up into the Farads except at low voltages. This sounds like something very special to me...

Probably have to make it up as a bank of smaller caps.

what is your usage? It will be a one off and very large and expensive. At this value voltage the inrush surge will be in the several hundred thousand amps. Also the stored charge will be lethal in more ways than one. You may have to series parallel a lot of lower voltage types, you may get a bulk buying discount!

Risky-yes.

Single piece--nobody makes.

Probably 400μF is the HIGHEST Eletrolytic Capacitor rated 400+VDC in mass-produced, Electronic Components "BAZAARS".So Parallel 425--AND YOU GET YOUR GIANT STORE of Coulombs

You need to carefully connect each of these to Giant Busbars justifying the Giant Coulombs stored/used.

And make sure--each of 425 has "instant-acting" Fuse or breaker.

And do not hope for HELP from the local fire service!

If you can, be willing to make this up as a bank of smaller ones. Be sure to either buy explosion-proof units or else put them in a suitable box. As I'm sure you must know, that's a heck of a lot of energy. My ole buddy, Siggy Myers, once put a .1F bank on a golf cart without enough R and took out a whole row of wall lockers.

Tom

Ever heard of Nitro capacitors?

Some modles have a far greater energy capacitor. try 8F@ 24VDC Max, and there're versions that have a far greater energy storage capacity than that!

170mF is a lot of wood - if it may be a little less you might have a look at the PCC-series of EPCOS. They have 7mF for 900V with L=367mm, W=195mm and H=256mm, only to give you an imagination of the sizes you request. Whats your application?

Regards Uwe

I use 450 volt, 4000uf caps made by Cornell-Dubilier. Others make them also. You would need 42 of these in parallel. At 400 volts you would be storing 26,880 Joules of energy. The real questions are how completely, how fast and how often you plan to discharge them. Their internal impedance will control the maximum discharge rate. They will need to be good quality if you plan to discharge them completely, and their life will be determined by the number of discharge cycles you anticipate. Oil filled capacitors are much bigger, heavier, and costly, but last almost forever. If you decide to use electrolytics, make sure you don't permit any voltage reversal. It will kill them. If you plan to use them for supply filtering, you don't need most of this information.

Are you sure you calculated correctly?

May I say if the answer to the above is YES, you should make a complete redesign of whatever you are trying to do.......it will be absolutely lethal if anything goes wrong!!!! as many have already said.....

Something is seriously and dangerously wrong here....

WOW,

Q=CV, that is 0.17x400=68

Q=68 Coulomb, Do you realize the amount of this stored energy?

What are you going to do with it that can not be solved in a MUCH simpler and so dangerous way?, (Not to talk about price.) Are you sure your math is OK?..

Just asking

Wangito.

Hi,

I can supply a variety of capacitors starting around 1 KV to 50 KV with ratings from 2 to 75 microfarads @ 1KV to 200 picofarads to 0.075 microfarads @ 50 KV. These are all meant to be used for quick charge/discharge cycles in Industrial Lasers (CO2 TEA type, ND-YAG , Ruby). Made by NWL, Maxwell Labs, Ceramite, TDK, etc...

The cap you're looking for would require a truck to move it.

One 40 KV cap rated at 0.075 microfarads can self charge in transit enough to be lethal so all terminals are shorted out for safety reasons.

If you're into designing high voltage devices I can supply you with limited quantity.

Get back to me If anyone is Interested.

Rick

Try the following:

http://www.tavrima.com/products.html

Had I access to alluminum oxide, I could make one and it wouldn't be the size of a truck. OK, its difficult to maintain dielectric thickness, plate uniformity etc, but it wouldn't be anything near a truckload. I've got experience building homemade super capacitors, and its damn difficult. I was building one capable of 50 V at potentially around 5 F when using the lowest Rutile constant value to calculate capacitance. (and so was using titanium oxided as the dielectric) mine arced... and I was peed off about that.

A lot of you guys are giving warnings, but this is just a passive device and a VA max of 68, and as I said earlier, the nitro variety have a far higher storage capacity being about 192VA max at 24 V, 4 F. Thats not to say that there's no danger, and in comparison a 24 V or 12 V battery is far more dangerous.

Thanks for the redesign suggestion andy, and I have redesigned my device to accomodate whats available. The capacitor I'm using has quite a low internal impedance... and thats good.

I hope everything goes as you plan it to.....

Have a great day.

Amazing, thanks very much andy! I get the sense that you mean it!

You have a great day also.

I always do mean what I say, even if it sounds sometimes unfriendly.....its the truth as I understand it and meant to help, never hinder....

But there are a lot of people on the web, not just CR4, that NEVER tell the truth!!! So it is not a surprise that you are surprised!!

Have a great day.

This would probably work: 390V, 17.8F.

That's more capacity than you need, but it's a nicely integrated unit. I'd think Maxwell could easily provide something smaller. Try not to short out the terminals once it's charged -- although I suppose it would all be over so fast, you'd hardly feel a thing.

Anyone Know where I might be able to buy one of these from? & What manufacturers make these, and what are the manufacturer's numbers?

talk to these guys:

www.maxwell.com

they make super caps.