Sciencemadness Discussion Board

identification of unusual electronic component, large.

Panache - 2-7-2012 at 05:01

Been meaning to ask about these two items for awhile, me being electronics inept. I believe they were used as part of a stepup transformer, they were in oil, the silver bases and top sheets are all highly polished aluminium, never felt anything so slippery and smooth.

Better question is what to do with them other than use them as chandeliers, which is their present task.

image.jpeg - 278kB image-1.jpeg - 275kB

watson.fawkes - 2-7-2012 at 06:22

The one with the zig-zag on it is a Cockcroft-Walton multiplier for high voltage. It's got ten stages, so that's the multiplication factor. Each of the diode assemblies (they look too large to have only a single junction) could well be rated 15 kV (that's 15 x 1 kV junctions in a single package). The whole multiplier looks like it might have operated at 100 - 150 kV. You didn't post of photo of the back side of the zig-zag, but I'd guess that's where the capacitors for the cascade are.

The other one looks like a stack of "doorknob" capacitors. There are six of them. A breakdown rating on these of 25 kV is typical; these could go higher.

All the polished and rounded metal is specifically engineered to suppress corona discharge. Submersion in oil is also standard for HV equipment; it further suppresses corona. Aside: oil doesn't always suppress corona, which is why self-quenching HV oils can be pricey.

So, it looks like you have the two main HV components of a very dangerous HV capacitor discharge system. As a trial calculation of its capacity, assuming operation at 150 kV and capacitors of 1200 pF each. Total energy storage is 1/2 CV2. For these values, that comes out to 81 Joules. That's enormous, and would be very instantly lethal, even for a smallish mistake. I have no irrational fear of HV, but this is no idle screwing-around gear.

Wizzard - 2-7-2012 at 06:36

I believe a baseball traveling at 60MPH has about 8J of energy, so that's enormous!!!

Twospoons - 2-7-2012 at 14:14

Quote: Originally posted by watson.fawkes  
That's enormous, and would be very instantly lethal, even for a smallish mistake. I have no irrational fear of HV, but this is no idle screwing-around gear.


Especially since HV at that level will reach out and get you - you don't have to actually touch!

edgecase - 2-7-2012 at 16:33

Sell it to Dr. Megavolt... I think his videos are on YouTube. Look for the guy wearing a large birdcage for a helmet, holding a wooden plank drawing a 10 foot arc.

Panache - 2-7-2012 at 16:57

Ok so chandeliers they stay beautiful things though, thanks for your replies, I much prefer understanding the description. If anyone in Melbourne wants the oil that watson mentioned pm me to arrange it it's about forty liters. I'll take the extra photos including ones of the 'mace' and 'gun' sections which where the large bit sticking into the large round gaps in the devices.
Is there any possibility of any pgm's in any of this stuff and if so which bit.

dann2 - 3-7-2012 at 04:35

The mother of all Birkeland-Eyde reactors for making nitric acid, anyone?
:D

watson.fawkes - 3-7-2012 at 05:20

Quote: Originally posted by Panache  
If anyone in Melbourne wants the oil that watson mentioned pm me to arrange it it's about forty liters. [...] Is there any possibility of any pgm's in any of this stuff and if so which bit.
The oil might be specially-made dielectric oil, or it might be relatively pure mineral oil. Both are used.

As for PGM content, unlikely. There might be some silver in the doorknob capacitors, but not a lot, since there are only two plates inside those. They're worth more whole, maybe 30 - 50 USD each (if I'm guessing right).

If you want to sell the parts, go on 4hv.org and post pictures. You'll get more salivation there than here. You could well get someone who wants this gear even after paying for international shipping. You should know that the rarest part is all the good machining and fabrication, not so much the electronic components themselves. Dimensions are matched though, so both are worth less if separated.
Quote: Originally posted by dann2  
The mother of all Birkeland-Eyde reactors for making nitric acid, anyone?
This is a pulse generator, able to fire every second or so; this is an educated guess (obviously). For the B-E process you need a continuous arc and a different power supply.

Panache - 20-7-2012 at 03:21

Quote: Originally posted by watson.fawkes  


Quote: Originally posted by dann2  
The mother of all Birkeland-Eyde reactors for making nitric acid, anyone?
This is a pulse generator, able to fire every second or so; this is an educated guess (obviously). For the B-E process you need a continuous arc and a different power supply.


what about one of these then (see attachment)?
My manual states the power supply is 280V Dc, 3- 5A, from a 240V supply (mains power), this feeds the high frequency power amplifier running 6 transistors.
from manual...'the driver system is controlled by the et51 gpp circuit via optocouplers. the small signals are amplified to the power necessary to drive the big transistors. This system is self-adjusting and gives exactly the basic-current which gives the optimal efficiency of the big transistors.'

goes on to talk about collector currents, impulse peak currents, resonance circuits, impulse generators, synchronized repition frequency (18kHz-35kHz depending upon which electroder you're using) and a whole lot of other stuff beyond me. It has a built in ozone extractor treatment unit.

and best of all it works! corona is a very pretty thing.

they retail at around AUS $125K, i got my one second hand with zero hours clocked (it was a second unit of two in a lab that never used it) for

AUS $100
for that price i had to buy it really, i'm from a poly film background so i knew its use, however it owes me a further $100 i spent on castors for it, its heavy. i should really try and sell it but i so loath cold calling i never try(seriously if someone in australia wants to broker this you can have ten percent of whatever you get, pm me)








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SM2 - 23-7-2012 at 06:24

I've found the best way to stumble upon such items is usually at something like a 3M or Imation auction. Also, certain government auctions. Turnkey, hand picked, matched, and ready to go (as Watson pointed out). Most the crap at military surplus retail level is, well, crap.

watson.fawkes - 23-7-2012 at 07:27

Quote: Originally posted by Panache  
what about one of these then (see attachment)?
Yes, a continuous output corona generator is certainly another application for such a multiplier.

I should also mention, however, that such devices can be, in certain ways, even more dangerous to work with than pulse discharge devices, because a corona generator may source more current than a generator that charges a capacitor bank. That is, these things can always deliver significant current, not just when their output capacitors are charged.