Safely testing 22 kV capacitors

On Fri, 31 Mar 2006 05:16:04 +0000, snipped-for-privacy@d-and-d.com (DoN. Nichols) Gave us:

With those caps, it would be kinder to all elements involved, including and perhaps even particularly the person causing the short.

Sounds like the fine beginning of a do it yourself rail gun kit

Gunner

"The importance of morality is that people behave themselves even if nobody's watching. There are not enough cops and laws to replace personal morality as a means to produce a civilized society. Indeed, the police and criminal justice system are the last desperate line of defense for a civilized society. Unfortunately, too many of us see police, laws and the criminal justice system as society's first line of defense." --Walter Williams

On Fri, 31 Mar 2006 02:49:16 GMT, Ignoramus27088 Gave us:

Those are HV resistors. At least I'd say it is quite likely. Probably 15kV or higher rating. They are Metal Oxide, likely 3 Watt units. Without actually hunting up the data sheet from victoreen, it is no more than an educated guess, however.

On Thu, 30 Mar 2006 16:19:47 -0500, Jeff Wisnia Gave us:

If you were observant enough of the thread, you would find that even the original poster mentioned the HV probe loading.

On Thu, 30 Mar 2006 20:55:59 -0600, "Martin H. Eastburn" Gave us:

More likely, they are change outs. Maxwell caps are only rated for a specific number of charge/discharge cycles. After that, expensive, tightly controlled lab environments want new caps so they know exactly how much energy they are working with on each stroke of the bank.

On 30 Mar 2006 19:01:34 -0800, Winfield Hill Gave us:

Are you a mexican illegal immigrant, protestor too?

I can't believe that you wasted so much of your time doing a statistical analysis on a technical thread which you haven't even posted any contributory response to. You are the antipathy of what it is to be "smart".

You're an idiot. Enough of ALL of the responses provided are archived, and would actually make reading the question for a given response easier than scrolling back up through the thread chain. What the f*ck are you doing mouthing off? You COULD actually try posting on topic, contributory material.

On Thu, 30 Mar 2006 22:51:35 -0600, "Mike Henry" Gave us:

However, the seller would not likely be able to get away with using the moniker either. I think it is legit, and I think they have SEVERAL "liquidation expediters" in their employ. The prices of these caps new means that whatever they can recover from the old change outs is that little bit more toward the whole budget.

Tim, I lost you a little bit here, sorry. Are you saying that I need single 30kV diodes and that putting 1 kV diodes in series is unsuitable? Or are you saying that twenty 1,000 V diodes is not enough?

Yes, tat would be very nice.

i

Yes, although I will probably keep one for myself.

Yes, you are right, it is indeed not easy. Thank you for your post, I saved it for future reference.

i

It's more likely that lab "junk" is sold off for salvage and that the salvagers or someone they've sold to are auctioning off the stuff. It seems really unlikely to me that anyone at Fermi Lab, or DOE for that matter, would bother to check Ebay seller names for usurpers of their "name". I haven't checked, but would guess that Fermi Lab's budget is at least a few hundred million dollars per year and technical staff probably bill out at around $125 and up per hour. They'd have to get pretty good prices for those caps at that rate to break even - did they?

Mike

--
NewsGuy.Com 30Gb $9.95 Carry Forward and On Demand Bandwidth

It is, doubtless, definitely Fermilab. I will go to him on tuesday into Fermilab itself. I find it difficult to imagine a private individual sellings his own things in this manner.

i

Roy, thank you. Sounds like they will be helpful.

i

[alt.marketing.online.ebay -- I am talking about an item that I won on ebay recently, see

]

Mike, I am going to Fermilab to pick up these capacitors on Tuesday and they want payment in form of checks made to Fermilab. They take my check on the spot and do not require it to clear. I would be greatly surprised if that was not a legitimate Fermilab operation.

I think that what we are observing is typical government/public funded surplus bullshit. I see the same stuff all over in military surplus. Everyone is going through the motions ("we are auctioning surplus to get highest competitive value"), but no one really cares to even understand what they are selling or what it costs to sell that stuff. Some things sell well for them (like high dollar electronic test equipment sold one piece at a time), some do not.

Now if this item was adequately described with love and care, then, I would suspect that it was not Fermilab but some private person who actually cares to get money for his stuff.

i

30-50kV PIV "diode", collectively. You can make that "diode" out of as many 1N4001 diode*s* as you need. :)

Tim

-- Deep Fryer: a very philosophical monk. Website:

News flash: the person doing the writing gets to decide how, or if, his work is distributed and stored. Demanding that he do it differently is no different than the people who ask a question and demand an email response. (equally stupid and arrogant, is the point I'm making).

Thanks, now I understand a little better. I will soon make a stack of, say, 30 1N4007 diodes. That would let me test the capacitors with 13 kV.

i

Dave, I sort of agree with both of you. I think that I have a right to hide my posts, but, on the other hand, I decided not to exercise it anymore. At least in this newsgroup.

i

Given that they were made by Maxwell and sold to Fermilab, they are probably spec'ed for pulse discharge. That said, I'd not want to be on the same city block when iggy crowbars them.

Putting a hard metalec short across them will no doubt blow half the terminal away, create a deafening blast and generate a nice EMP pulse. There's no way I'd do it.

Likely not, based on that label - it's simply something that, if you have ever had to deal with, you NEVER make assumptions about from that point on, because they were so widely used when they were in vogue.

--
Cats, coffee, chocolate...vices to live by