i'm just posting this thread in case i die in the next couple of weeks. OK THAT'S ALL DUDES
i'm just posting this thread in case i die in the next couple of weeks. OK THAT'S ALL DUDES
i'm just posting this thread in case i die in the next couple of weeks. OK THAT'S ALL DUDES
Would it be a side effect of the welder?
so i've worked out the final supercap specs. it's going to be a 14.1F capacitor with ESR of 100mU at 20v. i will be charging it to 18v and using it with at least a 200A thyristor for DC welding. peak current output will be 180A at 18v. it will be foot pedal operated but otherwise direct current. i toyed around with bringing current down then buck driving with a large number of beefy sinked darlingtons, but for efficiency and simplicity will just be putting the capacitor network together so that i can sink them directly into the welding point. (as it's a CD welder it can only weld points. it may have enough reservoir capacity to cut as well, but i don't expect to be able to bead long joints. frankly, it's mostly for making thermocouples and stitching the sides of sheet metal for the ssk plates).
i present this without comment:Show Image(https://dl.dropboxusercontent.com/u/24794081/2013-08-23%2005.54.59.jpg)
i present this without comment:Show Image(https://dl.dropboxusercontent.com/u/24794081/2013-08-23%2005.54.59.jpg)
i present this without comment:Show Image(https://dl.dropboxusercontent.com/u/24794081/2013-08-23%2005.54.59.jpg)
i present this without comment:Show Image(https://dl.dropboxusercontent.com/u/24794081/2013-08-23%2005.54.59.jpg)
i present this without comment:Show Image(https://dl.dropboxusercontent.com/u/24794081/2013-08-23%2005.54.59.jpg)
Safe handling guide: After unplugging, let it be for a few years to discharge. Then take long insulated grounded metal rods and poke around with them. Then use a large pair of plastic grippers and throw the entire thing in the river. It should now be discharged and ready to be left there forever.:))
Farad count on that?
i present this without comment:Show Image(https://dl.dropboxusercontent.com/u/24794081/2013-08-23%2005.54.59.jpg)
Safe handling guide: After unplugging, let it be for a few years to discharge. Then take long insulated grounded metal rods and poke around with them. Then use a large pair of plastic grippers and throw the entire thing in the river. It should now be discharged and ready to be left there forever.
Farad count on that?
Personally I don't trust cheap auto tint hoods. To me that is something that if it is cheap it is crap.
Perhaps also get some eye-drops (there are specific ones) in case you get a flash-burn anyway...
They are cheap, they help a lot, and it's a good idea to get em beforehand as you shouldn't drive or walk around with burned eyes, eh? ;)
Also, from my experience:
Mild flash-burn: Eyes are stoned red, they might burn somewhat, they are over sensitive to light, it might feel like you have dirt/sand in your eyes -> Usually goes away after a 1/2 day
Strong flash-burn: Eyes are demon red, you can't even bear room lighting, eyes hurt, strong feeling of having dirt/sand in your eyes, degraded vision -> Go see a doctor, really!
the cap network is fiberglass composite insulated and then JB welded to the heatsink. the fiberglass a massively effective dieletric, but has reasonably thermal conductance. more importantly, the cap network has very large surface area. the rectifier has a non-conductive steel plate over the internals on the down-side which is JB welded to the heatsink. i have thermal epoxy, but JB weld has significantly higher thermal conductance than that crap and much much more shear and tensile strength once cured. the power mosfets and the buck drivers need to be insulated so they'll probably get thermal epoxied at low pressure to maintain the dieletric properties of the thermal epoxy. back-sides and pins will all be potted with various grades of RTV silicone rubber depending on thickness needed etc. i toyed around with the idea of using silicone rubber as the dieletric and then JB welding, but the silicone rubber is a pretty extreme thermal insulator, so i'm going to stick with the thermal epoxy and generous potting.
one thing to note is that everything is very low voltage, so the chance of arcing is minimal. the reason to pot is mostly accidental contact.
(Attachment Link)So uh is there any chance this will blow up in your face?
cap network, 500A peak rectifierr, 33mfd smoothing cap, 750A of high speed power mosfet capacity. waiting for welding helmet before i make the first spark (have two copper chromium spot welder electrodes waiting for first spark as well). if i'm not seeing enough current at 18v, i will buck boost to 5v with a 200A (input, h_{fe} is about 1000) peak of darlingtons.
When you are looking at building mark II, I am pretty sure I could get you a number of these for next to nothing.
http://www.avx.com/docs/Catalogs/bestcap.pdf
I think they would probably work better for your purpose.
I would get a nice grounded rod with insulation to be able to discharge everything from a distance in case something is wrong. You do not want to have nothing happen and don't know why or what is charged or not.
I wonder how long it would take that charge to diminish naturally. Might as well build a concrete wall around it, add a pond on top and call it a day.
Edit: That sounded overly negative (pun), but I am just messing around. Looking forward to the results.
it works.
muahahahahaah