DC help required please

[truckdoctor]

Hi everyone great forum ,any expert out there that could help , I need to run 12volt DC at 15 amp continuose from the mains 230volt ac . is there something I can buy off the shelf , of could you recomend components I could assemble ? any suggestions please

[game a gogo]

I'm not an expert here... but I can help you get on track a little; first of all you'd need a transformer that would output 12v and then a rectifier bridge to transform the AC into DC, rectifier are easy to find; and possible to build them yourself as well. And for the amperage, I think you would need a voltage regulator that ouputs 15amps... which might be hard to find.

Also watch out if you do build something for this, 15amp is very deadly! I suggest you make sure you are well protected and never work in the circuit when you have it plugged! 1 amp can kill you, so 15... should knock you out easily, take safety mesure and make sure it is isolated when you plug it, never plug it when it's open-air, I wouldn't recomend that. Make sure of what you are doing and you are working safe; I can't tell you that enough. I hope everything goes well!

Oh and before I forget, do add a fuse if you can find one that is 15 amps. and make sure all your components can handle 15amps! Especially the rectifier, since I would assume that'd be the first to melt/break down to the current. good luck!

[nigelwright7557]

Amps dont kill its high voltage !

A transformer to drop to 12v then a high power rectifier, the smoothing capacitors, then a bank of transistors to regulate to 12v.
You will need a decent heatsink for this project and possibly a fan.

Might be easier to look into a PC power supply and see if one will supply enough current at 12 volts.

[coalex]

A 300W PC power supply can deliver about 14A at 12V so if you need more try to find a 320....350W one. I belive that even second one could be useful enough. About power it on if you find a AT PS is simple because it have an on/off switch directly to mains(220V ex.) but if you find an ATX PS to power on or off you have to short the gray (POWER ON REMOTE) to any black around. Be carefully that as long as the PS is connected to mains (even if switched off by remote) it delivers 3.3V at more than 10A so it is not dead it is still very alive. Hope this help. C.O.Alex

[coalex]

I have to correct myself. The PS has, on stanby, the 5V at about 1A (purple wire on the main board connector), and could be simply cut if not needed. Sorry for my earlier mistake. C.O.Alex

[fugro]

I see that there have been some very useful replies.
One point, though, re nigelwright7557's reply. It is the current that kills, not the voltage.
5v at 100amps will kill, but 5000v at a few microamps will just give one a nasty belt- as I found out many years ago when working with klystrons.
The best advice is to be very careful with both high voltages and currents.

[Martingrove]

Fugro, how do you get 100A through a living body at 5V?
M

[Martingrove]

It looks like this is required reading

http://en.wikipedia.org/wiki/Electric_shock

Martin

[BOCircuits]

A 300W PC power supply can deliver about 14A at 12V so if you need more try to find a 320....350W one. I belive that even second one could be useful enough. About power it on if you find a AT PS is simple because it have an on/off switch directly to mains(220V ex.) but if you find an ATX PS to power on or off you have to short the gray (POWER ON REMOTE) to any black around. Be carefully that as long as the PS is connected to mains (even if switched off by remote) it delivers 3.3V at more than 10A so it is not dead it is still very alive. Hope this help. C.O.Alex

Excellent solution, exact one I was going to suggest.
As for the person who stated "No, It's not current that kills, it's voltage"...that's incorrect. It is CURRENT that kills. Voltage is the push, current is the knife.