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Author: Subject: Power Source
tryptamine
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[*] posted on 20-7-2003 at 20:49
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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[*] posted on 17-10-2003 at 21:43
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:D 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
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[*] posted on 19-12-2003 at 14:05
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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[*] posted on 19-12-2003 at 16:20


You can get a 35Amp bridge rectifier for £1.29
How much current do you need?
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blazter
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[*] posted on 19-12-2003 at 17:24
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
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[*] posted on 19-12-2003 at 19:42
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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[*] posted on 29-12-2003 at 06:41


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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[*] posted on 29-12-2003 at 09:24


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.



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[*] posted on 5-1-2004 at 02:25


Wow, this is strange. After shorting the green to the black, the case of the power supply is now electrified :o 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 :D
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[*] posted on 8-1-2004 at 16:38


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?]




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[*] posted on 9-1-2004 at 01:45


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 :o Is that supposed to happen??


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.




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[*] posted on 10-1-2004 at 08:46


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 :o

I think I'll just stay clear of the case irregardless of its ability to conduct electricity :D
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[*] posted on 3-3-2004 at 20:27


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.




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