| Pages:
1
2
3 |
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
Schematic for Electrolysis Device
Prior to posting I searched quite a bit for a schematic for a Electrolysis design.
I have tried battery chargers but most today have an automatic shut-down feature that makes continued operation impossible.
Does anyone have such a schematic?
OR...has anyone found such a battery charger that would actually be used without spending a house payment?
We all know that the problem is that we are shorting the device. How do electro-plating devices function in that genre'?
I had thought of a charger going TO a battery and then to the solution but still th short makes most designs impracticable?
Any pointers, tips or actual designs would be deeply appreciated.
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
I'm out of touch with modern chargers but I presume you mean a thermal cut-out.
If heat dissipation is the problem you could bolt on a heat-sink or use a cooling-fan.
All you need essentially, is a suitable transformer and bridge rectifier.
Bigger tranformers are better since heat build-up is lessened.
|
|
|
bbartlog
International Hazard
Posts: 1139
Registered: 27-8-2009
Location: Unmoored in time
Member Is Offline
Mood: No Mood
|
|
Battery charger I have has a little switch to toggle between 'auto' (stops when it thinks the 'battery' is charged) and 'manual' (you stop it when the
needle tells you the battery is charged... or not, if you're running it for electrolysis). You might want to look for one of those.
Now of course that cutout happens when the resistance is too high... the opposite problem, shorting and overheating, are not something I've triggered.
But it seems to me that if your cell is properly designed, the resistance should not be so low as to short or overheat a battery charger.
|
|
|
Contrabasso
Hazard to Others
Posts: 277
Registered: 2-4-2008
Member Is Offline
Mood: No Mood
|
|
It's a supply of about 6v at about 25 - 250 amps that you need not a battery charger!Ebay will help as will the youtube vid of how to canibalise an
ATX PSU.
|
|
|
bbartlog
International Hazard
Posts: 1139
Registered: 27-8-2009
Location: Unmoored in time
Member Is Offline
Mood: No Mood
|
|
(car) battery charger and ATX PSU repurposing are pretty comparable in terms of capability, assuming you get a 25A or 50A battery charger. The ATX PSU
is cheaper of course, but you need to do a little work. With the PSU you get 5/12V whereas the battery charger will usually be 6/12V. In both cases
amps can be 20-50 with a decent sized unit.
Of course a real bench power supply would be far superior to either of these options.
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
I use a variac driving a stepdown transformer rated at 10 volts/10 amps. The transformer output is rectified by a Radioshack bridge rectifier rated
50 volts/25 amps. I have a voltmeter across the rectifier output and an ammeter in series with the electrolysis cell. Not particularly heavy duty,
but simplicity itself.
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
Thanks you guys:
I REALLY tried on this one but I am just not an engineering type.
Let me explain further because you all obviously know a Hell of a lot more than me here. When we speak of a thermal cutout, I am making the leap that
the switching transistors reach a point that they say "hey, we are getting hot from a full charge; let's stop". In this case, by making a more
efficient heat sink - I see the logic, however it would APPEAR we'd need a fan too to spread the heat or localized heat would also give the same
message...(?) no? Let's say that heat really does spread out... (logical) would that simply give me a bit more time for the same transistor to reach
the same conception OR do a larger more efficient heat sink keep that thing just under the "magic" switch number?
Now with a modern ATX power supply; doesn't that reach the same point? OR are the I.C.'s in there say "Hey fans; speed up, the machine's getting hot"?
I looked for a manual battery charger (the one bbartlog mentioned) but those are VERY tough to find. I found one made cheaply and it simply opened a
circuit breaker.
This project opened a whole host of things from pulling the HN4NO3 from CAN to making KCLO3 from water softener salt. The list is wonderful. But I
sadly have to admit I just don't have the "chops" to rig this fellow up. I had thought of getting a 12vhigh amp transformer and heat sinking most
everything + adding a fan. I DO have a electronics supply place in town that could hook me up with a 12v 20A, fuse it but I realized that the
rectifier would also have to be a tough one.
I also believe that since three of you guys obviously know some strong, effective solutions; I am making a mistake (wouldn't be the 1st one). If we
had to make a call on three differing methods: ATX supply, old fashioned battery charger, or a "hot-rod" charger (or similar) - which and why would be
the best be for a guy household electric experience & minimal electronic engineering knowledge?
I honestly appreciate any input, because realistically; I'm at a loss at finding a method short of the electroplating professional
machine (& I don't that much $ since I co-starred with Basil Rathbone in "The Woman in Green".
[Edited on 24-1-2010 by quicksilver]
|
|
|
Contrabasso
Hazard to Others
Posts: 277
Registered: 2-4-2008
Member Is Offline
Mood: No Mood
|
|
As a good method, get a 12v charger rated 25amps or more and drive it from a variac from your mains. That way you can adjust the voltage across the
electrodes to control the current flowing. Keep the high current wires short and fat, keep the variac well away from the cell and the fumes and
splashes. Ebay.com has several (hundred!) variacs some better and some nearer to you
It's the passage of electrons (ie current!) that does the work so though you may chose to monitor the voltage it's the current that matters
|
|
|
12AX7
Post Harlot
Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline
Mood: informative
|
|
Quote: Originally posted by quicksilver  | | When we speak of a thermal cutout, I am making the leap that the switching transistors reach a point that they say "hey, we are getting hot from a
full charge; let's stop". |
That works in some cases, like a moderate overload. More amps = more voltage drop = even more power dissipated = gradual temp rise past limits =
thermal cutout. OTOH, sudden overloads kill transistors instantaneously (~10us), for which I'm talking less than a 10x overload (for cheap computer
supplies, this point comes at about 0.5 times rated output!). In this case, the five dollar transistor protects the ten cent fuse. Fuses (and
thermal cutouts) are for protecting wiring, not electronics.
I'm considering building a 0-5V, 100A (adjustable volts/amps) power supply. Also considering power factor correction, universal input (80-268VAC with
no 120/240 switch) and synchronous rectification, resulting in efficiency around 90% -- low enough that it could be sealed inside a nice stainless
steel box (except for the small protruding aluminum heatsink) and operated in the same building as an electrolysis cell, with a long service life.
I'm guessing the cost would be a few hundred bucks, but it'll never die.
I could also extend functionality with digital controls and a timer -- potentially, a very long duration timer, such as "run for a week", or "run for
a million coulombs", both very useful for electrolysis. And I could add features like "stop if voltage or current exceeds xxx and note failure time".
Hmm, brownouts over that time scale are a possible problem; I'm not sure if it would be effective to store "where I left off at" in nonvolatile
memory, so it can remember previous settings, including interrupted run time. A brownout detector wouldn't work fast enough, but maybe a capacitor
would be enough to shut down on. Alternately, it could operate out of NVRAM (battery backed), or use FeRAM, which is NV without the battery. Ah yes,
they probably make little serial FeRAMs... that would be the ticket...
Tim
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
| Quote: | | I'm considering building a 0-5V, 100A (adjustable volts/amps) power supply. |
I made a low-tech version 12AX7.
It consists of a NST trans. sawn in half with the HT secondary removed.
If I want to, now, I can wind multiple secondaries.
The two halves fit back together nicely but it hums and vibrates something awful when running - but hey, it works; and it makes me work as well.
And of course I do a lot of guessing. . .
|
|
|
woelen
Super Administrator
Posts: 7976
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
I have written a completely worked out recipe for converting an ATX power supply to a power supply which can be used for electrolysis. With these
instructions even the really non-engineering type of people should be able to make a decent power supply for just a small amount of money. You might
even be able to get your hands on an old ATX supply for free, e.g. when an old out-of-date PC is replaced.
http://woelen.homescience.net/science/chem/misc/psu.html
Using 12 V directly for electrolysis is too much, you will have excessive wear of electrodes and a lot of side reactions and a lot of heat. Putting
two cells in series gives a double output, another option is to use series resistors for feedback control, allowing very constant and predictable
behavior of your cell.
I am very happy with this type of power supply. I can easily draw 10 A at 12 V from my supply, but modern 500 W supplies can deliver well over 20 A at
12 V (possibly divided over two separate rails). In my experiments, however, I seldomly draw more than 3 A from the supply. At higher currents the
cell may become very hot and you also can have excessive wear of electrodes.
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
@ woelen :
That was well done. I will give that one a shot ASAP --THOSE parts are free! I am actually impressed that so many folks have thought about this from
so many different angles!
|
|
|
pip
Hazard to Others
Posts: 109
Registered: 19-9-2008
Member Is Offline
Mood: No Mood
|
|
woelen would you know how to boost the power output on a pc type power supply but still for pc use? I have ran out of power in my xbox and need to
increase 12v power by an amp and the xbox uses a propritery power supply (I think)
I tried to figure it out myself and the best I can figure out is changing the tranformer, am I right and would anything else need upgrading?
|
|
|
Contrabasso
Hazard to Others
Posts: 277
Registered: 2-4-2008
Member Is Offline
Mood: No Mood
|
|
You will be very lucky if you modify a PC PSU for increased power, Better buy a higher power one.
|
|
|
dann2
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
Hello,
There are some circuits here that will give a constant current from a computer supply. They are not too difficult to build. A constant current supply is the biz for what
you are doing.
Dann2
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
I had completed woelen's design and was VERY impressed. Cheap, easy, flexible design. I HAD thought
of using a MOT with the secondary's modified, etc but woelen 's design made me actually laugh it's such a flexible good idea. - You could build upon
the basis of his idea to include other things. If I was to consider what to build I would do it again!
One of the issues with using HV parts is they are becoming very tough to get now. I have a little collection of NST's (nice old one like France) and I
don't know if I could get that stuff anymore. BUT MOTS and computer PSU....that's going to be free for a LONG time!
What I had thought about was replacing a modified MOT into a charger and upping the strength of the switching transistors and most other parts that
have a terminal level of current substantially lower than whatever I made from the MOT.
Simple, workable MOT design for 30 amp PSU:
http://www.youtube.com/watch?v=Yr8HKlX4VnU
[Edited on 7-2-2010 by quicksilver]
|
|
|
densest
Hazard to Others
Posts: 359
Registered: 1-10-2005
Location: in the lehr
Member Is Offline
Mood: slowly warming to strain point
|
|
Yes, woelen's design is very nice indeed.
A "quick and dirty" approach I have used is to salvage an appropriate connector from a discarded motherboard and attach all of the necessary
resistors and other wires onto that connector. The connector and attached tangle of wires needs to be glued or tie-wrapped to a board to be stable, or
(for someone less lazy than I) put into a box. It does save opening the PSU case and allows the PSU to be swapped out if necessary. All of the
resistor values, etc., that woelen specifies are applicable.
For a low voltage cell (silver or gold electrolysis, for example) the 3.3V or 5V outputs are very high current and are closer to the cell voltage,
thus needing to waste less power as heat to regulate the cell current.
For the electronics obsessed, here's an example of a switch-mode constant current source which could work well hooked to the 12V output: http://www.edn.com/contents/images/53002di.pdf It's limited to 2A by the LM2576; it would be easy to scale up to 20A or more with a different chip
and an external transistor.
The example as shown uses a TL082 dual op amp which requires +- 15 volts to operate (at least the + supply must be more than 2V over the highest input
voltage expected). More modern op amps such as the LM6132, LT1492, or LT1211 will work with V- tied to ground and V+ tied to the input supply. Other
more exotic chips such as a current sense amplifier like the LT6106 would allow high input voltages and use many fewer parts - only 3 resistors, 2 or
3 capacitors, the switch chip, catch diode, inductor, and current sense chip. The biggest disadvantage is that the current sense amplifier chips
mostly are not made in DIP packages so they are harder for a hobbyist to use.
Other interesting additions would be a voltage limit or monitor to alert the user or turn off the circuit if the cell voltage changes, for instance,
when the chloride concentration of a chlorate cell gets too low. Computer-compatible inputs and outputs for control and monitoring would be reasonably
simple as well.
@12AX7 - your "universal" PSU is interesting; maybe something like an expanded version of this as a post-regulator for a computer PSU would be a place
to start? Designing an off-line PSU can be exciting, but this would fit in a little box and have few safety implications... If anyone wants something
like this perhaps we could collaborate on something? Once this existed, adding the Heavy Duty front end is a separate project - for
instance, a 48V telecom supply picked up from EBay would serve.
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
Well then there's always HARBOR FREIGHT. They have some serious Chinese & Indian welders and chargers for about $100 and IF the base parts are
there and will stand up the idea of a very high amp PSU is possible.
There is a place near me that sell electronics surplus and has very serious resistors for x-ray, power station, etc application and those can be had
for about $9, making the cheap stick welders Harbor Freight has at $100 very much in the running.
But the idea of using a MOT - re-wound is a very simple way to get amps with virtually NO $ invested. I've torn apart monitors and TV's looking for
flyback transformers and other HV goods and found some 20watt resistors & since the standard CRT monitor is now a throw-a-way item the parts are
free.
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
It seems there are two ways to go if an individual does not get lucky and find a high end switching power supply: woelen's design or an OLD battery
charger that will maintain "manual" operation and not shut down. Those chargers are a lucky find in today's market.
I was looking at common battery chargers and opened a very common brand (Schumacher) but I could not determine the device that senses when the charge
has completed.
Since both concepts of PSU's are generally similar in price & availability, it would be a good thing if there was a way to make a 10A+ charger
maintain it's charging. I tried a parallel group of moderate wattage low amp resistors to allow the Charger to sense that "the battery" was still
needing a charge, but to no avail. Is there a way to get Battery chargers to function as PSU? Because now most all common brands are "automatic" in
their shutdown procedure to protect the battery from over charging; making their use on a continuum as challenging as an unaltered computer PSU.
|
|
|
woelen
Super Administrator
Posts: 7976
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
Im also experimented somewhat with battery chargers and it seems that these devices have some voltage sense circuitry. These chargers do not have a
stiff power output, but fancy wave forms are generated. A common mechanism is a pulse at fairly high voltage (e.g. 14 volts) and then the output goes
low (high impedance) for a while and at that time the voltage, delivered by the battery is measured. If that voltage exceeds a certain value, then the
battery is considered charged.
Some chargers also simply have a timer circuit, sometimes combined with some current sensing mechanism. Usually a simple controller chip in a SMD
package controls the entire system and you cannot easily locate the subsystem which does the actual shutdown. The SMD device can do the voltage
regulation, it can contain the timer, the wave form generator and the measuring circuitry at a high level of integration.
I quit further investigating a battery charger. Too much hassle because of the availability of another good alternative in the form of an ATX power
supply.
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
I am glad you looked into it. I had a feeling that there would be too many variables in different chargers and working with SMD's just seems a pain.
Perhaps in the future some will find a simple solution to the sensing issue (aside from dealing with some dead motorcycle battery in parallel) :-)
|
|
|
Contrabasso
Hazard to Others
Posts: 277
Registered: 2-4-2008
Member Is Offline
Mood: No Mood
|
|
With the advent of sealed batteries in cars there is a need to prevent people overcharging them and gassing away the electrolyte. So battery chargers
now sense something to determine a cut off time.
One of the hobby electronics shops in your country must supply a high current transformer with about 6 - 8 volts on a secondary with enough available
amps to make it a good choice. Then simply a bridge rectifier and a chunky rheostat to limit current and an ammeter. Simple and effective.
Added 546-165V7 from Mouser will be a great start.
[Edited on 18-2-2010 by Contrabasso]
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
| Quote: Originally posted by entropy51 | | I use a variac driving a stepdown transformer rated at 10 volts/10 amps. The transformer output is rectified by a Radioshack bridge rectifier rated
50 volts/25 amps. I have a voltmeter across the rectifier output and an ammeter in series with the electrolysis cell. Not particularly heavy duty,
but simplicity itself. |
I like your approach, Contrabasso!
|
|
|
Lambda
National Hazard
Posts: 566
Registered: 15-4-2005
Location: Netherlands
Member Is Offline
Mood: Euforic Online
|
|
Rewinding a MOT's Secondary with about One Winding per Volt Output works just fine, and they are free of charge. The MOT Transformer is very rarely
the culprit in a broken down Magnetron Oven, and at most, the secondary has shorted out, witch we don't need anymore. The Secondary winding is in
anycase removed, just be careful not to damage the primary winding during this procedure. And use sufficiently thick wire to rewind the Secondary,
better too thick than too thin. Car Audio Multi-Core Battery Power Wire is Thick and Flexible, or you can use Thick Single or Multicore Core and
Isolated Copper Earthing Wire used in Homes and Buildings. Single Core Copper Wire used at 50-60 Hz is just fine, for skin effects are irrelevant at
these very low frequencies. Just Don't rewind a Computer PSU with thick single stranded Mono-Core wire in this way, for skin effects then do play a
significant role at the frequencies used in these Units.
Dans Homebuilt arc welder:
http://www.dansworkshop.com/electricity-and-electronics/home...
How I Built My 70 Amp Arc Welder:
http://aaawelder.com/70amp.html
Mega Buzz Box 100 Amps:
http://aaawelder.com/indextoo.html
How-to: Build your own spot welder:
http://hackaday.com/2009/06/23/how-to-build-your-own-spot-we...
Micro Wave ovens are a source of treasures for the tinkerer:
http://www.home-workshop.com/MOTWelder.htm
Destructive Testing, 7V Rewound MOT:
http://www.youtube.com/watch?v=_AqItwvYq7s
I am fortunate to have Bridge Rectifiers of hundreds of Amps, but if you are not, then eBay may be the solution. Or, you can wheedle them out of a Car
(12 Volts) or Lory (24 Volts) Alternator/Dynamo. You guys are creative enough to find "Free" sources like I do, from old Lift Motors (or what ever,
even old Crane or Industrial Motors) and old Mainframe Computer Supplies (MOT not needed anymore) found in scrapyards. Or just become a Dumpster Diver
like me, it's fun and rewarding too. Money lies on the streets for those who seek, and find ...
Lily Allen - The Fear:
http://www.youtube.com/watch?v=q-wGMlSuX_c
Lambda (Always Diving where the Sun does not Shine, ... and my Girlfriends love it  )
|
|
|
Lambda
National Hazard
Posts: 566
Registered: 15-4-2005
Location: Netherlands
Member Is Offline
Mood: Euforic Online
|
|
40 Amp Power Supply Unit
http://www.qsl.net/vu2upx/Projects/40apsu.htm
*Input voltage: 240
*Output voltage: 13.2V DC
*Output current: 40A DC
*Over current protection: current limiting al 40 Amps
*Short circuit protection: Regulator shut off.
*Over voltage protection: Shuts off DC input and discharges input stage reservoir.
*Over temperature protection: Fan automatically operates as heat sink temperature of 65°C.
*Indicators: Power ON LED and Short circuit Protection active LED.
This Power Supply concept is based on the popular 723 Chip, and can easily be re-engineered to fit our needs. Schematic and PCB
included, to give you an impression of the simplicity of this design. It also uses remote sensing, to compensate for voltage drop over the Supply
cables. However, constant current would fit our needs better, if used in an electrolysis setup. Regulation down to about 0.7 Volts would not work at
40 Amps in this setup, for too much heat would then be dissipated via the Output Transistors. Lowering the input Voltage via a variable Transformer
Junction Tap, the use of an Variac Transformer pre-regulation (Tricky Concept), Triac or FET pre-regulation would work out. The 723 Chip would then
need a separate small Power Supply Transformer to feed it. You still won't get the High Efficiency of a SMP, but you will have a virtuously
indestructible Lab Power Supply which can also be used for other purposes, even to Charge your Lead Batteries with.
Carpark North - Shall we be Grateful (HD):
http://www.youtube.com/watch?v=-R1RQniPohI
Ladyhawke - My Delerium (Fan Death Remix):
http://www.youtube.com/watch?v=XlNIlnC6Hsk
Veronica Maggio - Måndagsbarn:
http://www.youtube.com/watch?v=NtJxy0zc7nU
Lambda
|
|
|
| Pages:
1
2
3 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
