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tryptamine
Harmless
Posts: 16
Registered: 20-3-2003
Member Is Offline
Mood: elated in love
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MOT
A rewound MOT is the way to go here(better yet a bank of rewound MOT's), you want high amperage. Using any other transformer anything you are
trying to accomplish will take forever and a day. Searh online for a guy that made a huge ac welder using 8 MOT's. If this doesn't convince
you of the suitability of these transformers nothing will.
Rectify your transformer output with a bridge of high amp diodes or an SCR/pulse generator combo.
There is no other practiucal way of doing this short of going out and dropping several hundred on a heavy duty rectifier.
I'm building a power supply like this right now in fact, I'm probably going with the SCR setup cause I might be able to get some enormous
Toshiba's or Fuji's from work, plus it makes it easy to vary the load.
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fogus
Harmless
Posts: 2
Registered: 17-10-2003
Location: Vancouver
Member Is Offline
Mood: hopeful
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voltage concentration etc.
Hi,
i am absolutly new to this sight, i hope that this works (i have had worse luck with other sights)
While working with electrolising potassium perchlorate I have herd that a good electrolising solution is one which uses a one third concentration of
salts (potassium cloride by weight) and a low voltage of 3V is most efficient. I got this from a smart person and i was wondering if this was true or
not.
i have been trying to make potasium perchlorate for a long time now and i might have my first batch today i am waiting for it to dry. i am hopeful that it electrolised properly. if it didnt i wont give up. this will only be
one more thing that doesnt work.
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blazter
Hazard to Self
Posts: 71
Registered: 3-9-2002
Member Is Offline
Mood: No Mood
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old AT power supply problems
I managed to scavange an old AT power supply from a scrapped compaq computer. It doesn't seem to have a wattage rating, but it does claim to be
able to supply 14A at +5v. This power supply would seem to be perfect to resurrect my chlorate cell which ate up a 25A bridge rectifier after about
an hour of operation. With any luck i'll have a better, voltage regulated supply this time around.
Anyways, I found some pinouts to the motherboard connectors, and it seems to check out when they are metered. This power supply appears to run
without a load with no problems. The problem which I run into is that the voltage drops dramatically when the electrodes are immsersed in the salt
solution. It appears to go as low as a fraction of a volt. This effect seems to depend on how far the electrodes are immersed. When only a few mm
below the surface things seem to go well with the voltage slightly below 5v and many bubbles.
In an attempt to fix what appears to be a regulation problem, I shorted the power good lead (pin #1 orange) to a ground. In addition all the grounds
seem to be common as they all give continuity to the chassis. This seemed to do nothing at all in regulating the voltage.
The other thing that should be noted, is that based on the amount of gas evolved by the test cell would indicate that there is no where near 14A going
through the outputs. Just a wild guess, but its probably less than 1A based on the amount of bubbles produced (more on this when I hook up an
ampmeter).
In an attempt to slightly load the +12v and +3.3v lines, I stuck small 12v pilot type bulbs on them. The funny thing is that the one on the 12v line
seems to glow brighter as the voltage decreases on the 5v line.
Also, if I can ever get this working, I plan to hook up a 60w 120v lightbulb in series to the cell. The idea here is that the bulb will limit the
amount of current which the cell can draw (hopefully) protecting it. In theory, running at 5v the bulb should allow at most 12A to flow through it.
Any suggestions on how to get this thing to supply the current which it claims to would be greatly appreciated. If all else fails, or it goes up in
smoke, theres another AT power supply waiting 
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unionised
International Hazard
Posts: 5102
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
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You can get a 35Amp bridge rectifier for £1.29
How much current do you need?
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blazter
Hazard to Self
Posts: 71
Registered: 3-9-2002
Member Is Offline
Mood: No Mood
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the more the merrier
For this chlorate cell which consists of salt solution in a 1 gallon glass jar, the more amps the better. Just getting 12A from the power supply
which I have on hand would be just fine.
I'd really like to use these AT power supplies since they are on hand doing nothing, and are free. Some others have reported success with them,
and I would be very interested in any secrets to getting it working properly.
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Mr. Wizard
International Hazard
Posts: 1042
Registered: 30-3-2003
Member Is Offline
Mood: No Mood
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link to super do it yourself electronics
This guy has a site with all sorts of ingenious do it yourself power supplies. He seems to specialize in redoing older items that are available:
http://www.qsl.net/xq2fod/Electron/Electron.html
he has no connection with Mad Science
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Saerynide
National Hazard
Posts: 954
Registered: 17-11-2003
Location: The Void
Member Is Offline
Mood: Ionic
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I hooked up the 12v at 8 amp pins on an old computer power supply and got no luck... It doesnt seem to work unless its plugged into the comp... I
tried pluging in a cdrom and floppy drive and still no luck 
Any hints?
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I am a fish
undersea enforcer
Posts: 600
Registered: 16-1-2003
Location: Bath, United Kingdom
Member Is Offline
Mood: Ichthyoidal
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PC power supplies will only deliver power to peripheral devices when instructed to do so by the motherboard. With ATX power supplies, this can be
done by shorting the green PS-ON lead to any of the black ground leads.
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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Saerynide
National Hazard
Posts: 954
Registered: 17-11-2003
Location: The Void
Member Is Offline
Mood: Ionic
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Wow, this is strange. After shorting the green to the black, the case of the power supply is now electrified  Is that supposed to happen??
And why is there no negative lead for 3.3 volts? On the key, there is no negative compliment for "+3.3 v 14 amp", only something that says
"+5 Vsb" Does anyone know what that means?
Btw, my power supply works great for electrolysis now, but it cant hurt to have an extra voltage/amperage choice
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Star
Harmless
Posts: 14
Registered: 8-1-2004
Location: Crozet Islands
Member Is Offline
Mood: Closing Edge
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After you have got your hands on a AC power supply[which basically is a transformer ] ,you must be able to regulate the output right?
The law of Ohm :I=U/R
So if you want to have the right amperage you must know the internal resistance of the electrochemical cell right?[whats the resistance of a NaCl
solution?]
Crazy litlle mad angry edgy precious malicious amateurs,...hihihi
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I am a fish
undersea enforcer
Posts: 600
Registered: 16-1-2003
Location: Bath, United Kingdom
Member Is Offline
Mood: Ichthyoidal
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| Quote: | Originally posted by Saerynide
Wow, this is strange. After shorting the green to the black, the case of the power supply is now electrified Is that supposed to happen??
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I don't think so. It's possible that your power supply is faulty and that one of the previously switched off power lines has shorted to the
case.
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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Saerynide
National Hazard
Posts: 954
Registered: 17-11-2003
Location: The Void
Member Is Offline
Mood: Ionic
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I had 4 different ppl touch the power supply box to see if it was electrified. 2 said it was, 2 said it wasnt and that it was only the vibration of
the fan
I think I'll just stay clear of the case irregardless of its ability to conduct electricity
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CommonScientist
Harmless
Posts: 24
Registered: 7-2-2004
Location: In front of a faulty nitric acid still
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Mood: Tense
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I used a 3A 12V battery charger. I have a IBM PC pwer supply, pics of my cell and power supplies http://img23.photobucket.com/albums/v68/CommonScientist/Chlo...
The only problem with it is that it ran in cylcles, on and off. It would shut off, turn on , so I dont know how long it actually ran. I have some RC
car battery chargers. TYCO R/C one is 11.5 V 1.085A, which is nothin really.
\"rules are for the guidence of the wise, and the blind obedience of fools\"
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