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Obligatory stuff from Three Phase: https://www.youtube.com/watch?v=42Kn9JlXE5w https://www.youtube.com/watch?v=GSiRyl4b8Yw https://www.youtube.com/watch?v=pCZax3vIslo https://www.youtube.com/watch?v=Lw3k3Un9pNk https://www.youtube.com/watch?v=VSrpc8nxnHM   Who the hell uses 347V?https://www.youtube.com/watch?v=OZ0onadvC48 https://www.youtube.com/watch?v=hIkNY5xjy5k https://www.youtube.com/watch?v=9z77oztO6UQ :germany: Three-Phase fucked around with this message at 23:41 on Jan 11, 2015 |
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Jan 11, 2015 23:37
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C.M. Kruger posted:https://www.youtube.com/watch?v=Rlb64Is-fhY That wasn't easy but I found it. It was a circuit breaker. They removed (broke off?) the operator mechanism, and gravity caused the internal bit to slide down, eventually the contacts inside the vacuum bottles touched, and the output connectors that they thought had only 20V (residual) on them became energized with 20 thousand volts. https://www.youtube.com/watch?v=yXU0jiBQfG0 Alternative version with jaunty soundtrack! Three-Phase fucked around with this message at 04:45 on Jan 13, 2015 |
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Jan 13, 2015 04:34
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What a strange trick.
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Jan 14, 2015 00:46
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Van Kraken posted:While looking for the source of this I found a video of this terrifying cave in Wisconsin: That video is going to give me nightmares. 
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Jan 15, 2015 02:21
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Is that an actual ladder or just cable tray? The cable trays I've seen have "THIS IS NOT A LADDER - DO NOT USE AS A LADDER OR WALK ON THIS" warnings on them.
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Jan 15, 2015 02:22
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Nierbo posted:This was at a job site I was just at. Anyone know what the heck it means? I think it's a transformer. Size: 1500kva (kilo volt amps, sort of like a watt rating) Primary: 13800 volts (standard voltage for power lines along the road providing power to small or medium industries) Secondary: 4160 volts (standard voltage for moving power around factories, also some larger motors can run at 4160) How big is the box? For medium voltage to medium voltage, it might be an oil filled transformer. I've seen ones that are air cooled that were 7200V to 480V in a factory. A medium voltage generator would be really big. I don't think they make "portable" generators higher than 4160V. Three-Phase fucked around with this message at 20:35 on Jan 18, 2015 |
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Jan 18, 2015 20:32
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Tunicate posted:I was thinking one of those big caterpillar generators, but a transformer makes more sense. Sometimes you also see a format like this:
The D and Y are for "delta" and "wye" connections, and the BIL (basic impulse level) is basically how much of an impulse it can withstand from a lightning strike, like a sudden surge to 100,000 volts. Be aware that on some industrial generators, you can change the connections inside to change the output voltage levels. Three-Phase fucked around with this message at 23:26 on Jan 18, 2015 |
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Jan 18, 2015 23:23
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boo_radley posted:Do not challenge the machine. Is that even salvageable or is that an "amputate immediately" thing?  I would be amazed if that could be recovered at all. Any doctors in the house willing to give their opinion on this? EMILY BLUNTS posted:the plastic ones will do that after enough time, too I went and got a bamboo one. The plastic ones generated WAY too much static electricity. I would touch my computer case and it would BSOD. Three-Phase fucked around with this message at 21:38 on Jan 19, 2015 |
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Jan 19, 2015 21:36
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I would think with the loss of blood flow the chunks of tissue would be dying and there's no way to get that all meshed back together, let alone thinking about how to reattach nerves, arteries, tendons, and so forth.
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Jan 19, 2015 23:29
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Das Butterbrot posted:pretty good, but its no staplerfahrer klaus It's also no "Think About This". I think the lady singing might be drunk. https://www.youtube.com/watch?v=0GXcbReCYwM (RIP North Bus Duct 1982-1993)
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Jan 22, 2015 00:29
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Aren't zip lines supposed to be at an angle less than 45 degrees? Wasn't there a Goon awhile back who was designing/building a zip-line-of-death and he got called out that the thing was a complete deathtrap?
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Jan 25, 2015 01:57
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If someone has an animated GIF of Hank Venture jumping off the roof with an umbrella, please post it.
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Jan 25, 2015 02:23
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Gorilla Salad posted:Passive aggressive OSHA I always thought those transformers came powder-coated from the factory that way.  I've seen some pretty sweet murals done on utility boxes and transformers. As long as they don't paint over the identifying information and warning labels, it seems pretty cool. Three-Phase fucked around with this message at 00:24 on Jan 30, 2015 |
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Jan 30, 2015 00:19
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Thump! posted:
I've heard of balanced loads before, but that is ridiculous! 
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Jan 31, 2015 00:01
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It's like a safety soap opera. Awesome. https://www.youtube.com/watch?v=osy2cGfmEAQ I don't know what happened here, but I'm pretty sure that thing's not supposed to do what it did. I'm waiting for planes to have some kind of emergency self-land functionality.
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Feb 3, 2015 00:03
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Cool! Leperflesh posted:During the stoppage, managers are doing the jobs of the workers, which is obviously perfectly safe and not a problem at all, one assumes. This will almost certainly end in tears. And a CSB video. You know, with the 3D animated people. Three-Phase fucked around with this message at 01:29 on Feb 4, 2015 |
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Feb 4, 2015 01:26
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Process.jpg Hmm... (not from where I work!) Hint: Look at where the arrows are pointing... Three-Phase fucked around with this message at 01:11 on Feb 6, 2015 |
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Feb 6, 2015 01:06
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As far as the float video from last page - according to this the guy survived the shock, the deaths were from panicked people stampeding into the crowd after it happened. http://www.foxnews.com/world/2015/02/17/multiple-deaths-reported-as-power-line-falls-on-haiti-carnival-float/
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Feb 17, 2015 23:27
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Minrad posted:For something more OSHA, "Now they tell me..."
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Feb 18, 2015 01:32
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Willfrey posted:Ugh, don't wear loose loving clothes near lathes. Or any rotatory. I dislike wearing even long sleeves. At this last machine shop I worked at we had a guy there who had the 'inside line' on a bunch of fatality photos from machine shop accidents. Worst one I saw was a guy who's arm got sucked into a lathe, wrapped around it, and pulled him up to his shoulder, whereupon his head got sucked between the backstop and wedged in.. blah... I've been at a motor shop where people routinely work around exposed motor (and generator) shafts to do things like check balance and magnetic center. They are confident but it always scares me when that thing is spinning at 900 or 1800 RPM. instead of a couple of horsepower these things can be as high as 10,000+. Plus the electrical leads are as high as 14kV.
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Feb 21, 2015 13:46
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Ugh. What a hack job. Regarding fire extinguisher training - we had it at work, and one of the thing emphasized was that the fire extinguishers were there to stop small things like a fire in a trash can, or a small piece of equipment. We were ordered that if there was a big fire, like a room was engulfed, to forget the extinguisher and get out. We were also advised that if we chose to "play fireman" in a situation like that, we could be punished up to termination. It does make sense. Also, one of the manuals for a medium-voltage drive (sort of like a dimmer switch but thousands of times larger) at work warns if you see smoke or flames coming from the drive, press the e-stop (on the drive) and don't use water to fight the fire. If the drive was on fire there's no way in hell I would walk up to it and press the e-stop.
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Feb 26, 2015 11:59
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Methylethylaldehyde posted:By 'press the e-stop', they meant 'the big "oh gently caress me" switch outside next to the distribution gear'. Anything bigger than about 100 KVA and there is sweet gently caress all you could do to convince me to get near it when it starts to arc. There is a really good reason why the highest level arc flash PPE look sorta like foil covered bomb suits. It's much higher than 100kVA. Only time I've seen Level 4 suits being worn was when they were racking 7kV breakers into a hot bus by hand. They don't do that anymore, they use a robotic racking system. So for the foreseeable future, the Level 4 suits are probably going to collect dust. My own personal suit is Level 2. I've only used it once or twice, I remember using that when doing diagnostic work with exposed 480V motor control center equipment. CzarChasm posted:If you can think of an easier way to put three outlets right the gently caress there I'd be glad to hear it. Could you put in flexible metallic conduit from the breaker panel down to a box with a quadruplex outlet? (EDIT: I think you cannot install that where it's subject to physical damage, so you may need to put in actual conduit. There's EMT, that's metal tubing that's super thin, and you also can't use that in any area where you might be able to damage it.) Three-Phase fucked around with this message at 01:39 on Feb 27, 2015 |
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Feb 27, 2015 01:33
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IndianaZoidberg posted:Opening a 500kV switch That switch is never supposed to open with current flowing through it, it's used for isolation. Like turning something off then unplugging it.
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Mar 15, 2015 11:33
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Ambrose Burnside posted:IIRC the problem is that dimmer switches wreck the... what is it, the AC 'wave pattern'? Light bulbs don't care but more complex tools and appliances can be damaged or have their lifespans cut drastically short by that kind of uncontrolled current. A dimmer switch using a triac basically chops up the AC waveform. So you get "chunks" of it instead of the whole sine wave. Imagine one cycle of a waveform. If it fires (gates) at 90 degrees and 270 degrees, you'll get nothing, then the "right half" of the first hump, and then nothing, then the "right half" of the second hump that goes negative. It basically acts as two check valves that can be activated at a certain point on the sine wave. With a rheostat, you add an additional load in series, so you end up dropping the voltage the load sees. You can also do this with a transformer. You can do this for smaller induction motors, but if you want to change the speed of a bigger induction motor, you need a drive that takes in 60Hz (or 50Hz for people living in weird countries) and changes the frequency - a variable-frequency drive or VFD. These generally (except cycloconverters) take AC, turn it into DC, then turn it back into AC. Or you can make a motor-generator with a DC motor spinning an AC generator. Three-Phase fucked around with this message at 22:58 on Mar 16, 2015 |
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Mar 16, 2015 22:55
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Oh cool this got moved back to GBS. Word on the street was that there was a very serious arc flash accident at Los Alamos National Laboratories recently. http://ecmweb.com/fire-security/los-alamos-national-lab-worker-burned-substation http://www.koat.com/news/worker-burned-at-los-alamos-national-lab-in-critical-condition/32806058 There are some additional details floating around the industry - 2400V system (not as common as 4160V for modern plants but still used in places), guy near the equipment got burns over 95% of his body. And there were people standing 20 feet away that also got burns (some pretty serious) from the arc and copper that was thrown. None of the people involved in this incident will ever be the same.
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May 12, 2015 11:25
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Say Nothing posted:
Fun fact - some of the fuses I use at work have strikers - not quite like the bullet, but when they blow there's a tiny explosive that pushes out a metal pin. Usually that's used to protect motors - so if one of the fuses blow, the pin pushes out, slams against a big plastic bar, and that presses a switch, and the switch opens the circuit breaker so the motor doesn't run single-phased. (That's bad.)
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May 12, 2015 11:31
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Minor shock while vogueing. https://www.youtube.com/watch?v=sOshAZVPbv4
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May 25, 2015 13:07
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Decrepus posted:Unless I'm mistaken about which video it is, he wasn't vaporized, he was blasted into the back panel and stumbled down the hallway while his clothes were on fire and melting into his skin and ran around the plant for a bit before being extinguished and dying in the hospital. They found his burned flesh and clothes in a trail and on the door handles. The person walking into frame was also severely burned. I'm late on this one, but that was another incident at a plant in the US. Basically, the electrician was sent to troubleshoot a motor starter where the fuses had blown. He opened up the starter compartment and went to check the voltage across the fuses to find which one(s) were blown. The problem was that he thought it was a 480V system. It was, in fact, a 2400 volt system. The meter he had was likely only rated up to 600 or 1000V. The instant the probes touched the fuse blades that were electrified with 2400V, an arc occurred inside the meter, and milliseconds later you had enormous current (many thousands of amps) flowing through the meter. The wiring vaporized, the meter exploded, and generated a tremendous arc flash. He was blown across the isle into the back of another switchgear line up, he then stumbled across the room with his clothes on fire. As far as the video of the guy getting blown up in the switchgear: he was racking a breaker in or out of a hot bus. Where I work, we have "racking robots" that do it. Here's a video of one company's racking system racking out a GE breaker rated at 13.8kV, 1200A (28 megawatt capacity, enough power to run a town): https://www.youtube.com/watch?v=FUEAbYl0NbU These breakers are oddballs because instead of racking into the bus by being pushed backwards, they rack UP into the bus above them. If that was a live bus at that voltage and current I'd be standing WAY back from where the guy in the video was. If you're dealing with power distribution systems, the arc flash can be so high you can get burned standing pretty far away from it. (There's also the danger of thrown shrapnel, copper splatter, stuff like that.) It still beats the hell out of this - and the closeness is why racking circuit breakers on live busses are so dangerous: https://www.youtube.com/watch?v=iWWtsYdc2pM This video from GE is a bit of a "how stuff works" look at some of their gear, the insides. https://www.youtube.com/watch?v=3YayEOC_btQ That e-stop (where you need to turn THEN push) is a bit... odd... Three-Phase fucked around with this message at 14:03 on May 30, 2015 |
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May 30, 2015 13:52
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Mooseykins posted:There was a time when i wanted to be an industrial electrician. I work with industrial electricians all the time. Like any job with hazards, there are procedures in place that keep people safe. From an engineering standpoint, there are guidelines for designing systems that keep people safe. Probably one of the biggest dangers is if equipment has been modified or the drawings showing the equipment is outdated or incorrect. Never blindly depend on system documentation.
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May 30, 2015 22:19
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Manuel Calavera posted:It's probably a safer job overall than being a cook! Knowing nothing about the injury rates for both industries, I'd still say that. Just based on my experience as a cook. Probably true. I finally found that Dawson Mine high voltage arc flash re-enactment video. It's OSHA.mov as hell. https://www.youtube.com/watch?v=yXU0jiBQfG0 The solution gets more and more convoluted as the video goes on, especially when they drill and tap holes to install bolts to hold the spring tension when removing the circuit breaker operating mechanism and then try to pry it off the assembly.  
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May 31, 2015 00:21
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-Zydeco- posted:Why doesn't gear like this with physical disconnects have a visual inspection window? Tiny bit of added cost and the possibility of dirt getting into the mechanism? High voltage disconnect switches that are outdoors - you can see the switch position because they're in the open air. For indoor disconnects, a lot of them have viewing windows that are standard built-in. That's part of the operating protocol - you operate the switch, then you visually confirm that the blades are all either open or closed. As far as other equipment goes - one reason may be that the viewing window would be a weak point if an arc occurs inside the gear. Plus during operation of older breakers that don't have vacuum or SF6 bottles, you'd have the light from the arc shining out and that could cause vision damage. Also for a breaker like this with vacuum bottles, you cannot peer into the bottle itself and verify the contact status, you can only see where the operator is at (open, closed, or "travel" position). RandomPauI posted:In my personal opinion a person should always have copies of their manuals readily accessible whether they're working mass care, feeding, client casework. There's no reason for that not to apply to electricians working with high voltage equipment. The problem is when you're working on equipment that was installed back in the 60s or 70s, and the manuals are long gone. Also, going online and getting manuals from companies is a crapshoot. Many don't keep manuals from way back, sometimes that data is lost when Company A buys Company B, and some companies just don't want to give people their manuals. Also, a lot of times the manual may treat systems that engineers want to peer into as a black box. Some companies are, in my opinion, extremely protective of their manuals and IP (ABB). Others are really good about it, but you need to register with them first before you download their manual PDFs (SEL). And some will only give you manuals if you pay for them, but that's uncommon. Three-Phase fucked around with this message at 15:09 on May 31, 2015 |
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May 31, 2015 15:05
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Mooseykins posted:In that video, it said that they switched the gear to open, but by gravity they closed themselves, and even if they'd engaged the second mechanism (?) the switch things still would've dropped and turned everything live. The carriage that operated the vacuum interrupters was always supposed to be connected to the operator. By defeating the interlock and prying it off, there was no longer any mechanical connection so it just slid down due to gravity. When they removed that, all bets were off. The switch design might have been janky as well. Probably made to be inexpensive and easily installed/removed for this kind of application. If I was designing this, I'd have it built the other way around so that if the linkage was damage, the circuit would open on its own rather than close. When the guys were designing the switch, they may have done an FMEA (Failure Modes and Effects Analysis) that went something like this: FAULT: Breaker mechanism closes unexpectedly EFFECT: Unexpected equipment operation, exposure of personnel to high voltage/arc flash CAUSE: Incorrect operation CAUSE: Linkage fails to keep carriage in the correct position (moves due to gravity into closed position) - Operating mechanism damaged - Operating mechanism vandalized/removed And the guys probably crossed out the "operating mechanism vandalized/removed" because it was such a remote possibility. Except in this case it wasn't. From a legal standpoint too, once you've modified equipment, all bets are off.
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May 31, 2015 15:27
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https://www.youtube.com/watch?v=0xavqHI33QE "Hello Masha! I feel all your thousand roentgens with a familiar chill of mild fear..." "From the winch to the chimney was around 70 feet. You can approach around 10 meters. No more. OK, a little bit more. OK, stop, you cannot go any further. Here's our cutie. It's overridden a graphite block. It's now sitting on a 12,000 roentgen fragment, like a hen on it's nest." Fast forward to 2015 - here's a video showing the New Safe Confinement structure being readied. https://www.youtube.com/watch?v=JRdlAzLiPC0 Three-Phase fucked around with this message at 19:44 on May 31, 2015 |
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May 31, 2015 19:34
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Ulf posted:Your second video here is by a woman who likes to sneak through Chernobyl and Pripyat digging through dusty barrels looking for nuclear fuel / toxic waste to play with. Strange woman, can't remember if she has been featured in this thread or not. https://www.youtube.com/watch?v=9LN2V4DsP0s There were radioactive firefighter uniforms in the basement. She said that people took the firefighter helmets as souvenirs. I guess removing a small clothing fragment for analysis isn't quite so bad.  And yes, what she's doing is pretty dangerous. My biggest concern would be getting a hot particle on my skin or worse, inhaling/swallowing one.
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Jun 1, 2015 21:38
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Some additional nuclear stuff: "Criticality 1969" https://www.youtube.com/watch?v=r3fWhW_NsMs "Dangerous geometry" would be an awesome band name.
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Jun 2, 2015 23:59
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Little problem at the power feeder for a factory. Very pretty when it's blasting molten copper everywhere. http://www.liveleak.com/view?i=b36_1361303716 For the full effect, turn your volume all the way up. Found this one too. 69,000 volt transmission line plus apparent untreated mental illness is one hell of a bad combination. https://www.youtube.com/watch?v=Zr3N2dSEEVM   He survived! Three-Phase fucked around with this message at 12:44 on Jun 6, 2015 |
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Jun 6, 2015 12:24
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VectorSigma posted:Yeah that's the vibe I got. The only thing I can think of that might have allowed him to live would be the path of least resistance moving quickly over into the plasma channel of the arc and away from his body. Even then, no matter how brief the initial jolt was, that had to be one hell of a flash. The camera just goes white. It's at night too, so the camera is trying to amplify light as much as it can, so that probably doesn't help. The light show was much more spectacular than the "one man one pantograph wire" video.
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Jun 7, 2015 01:13
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http://www.reddit.com/r/OSHA/comments/39173q/standing_on_back_side_of_aluminum_ladder_with/ I believe this is a Bitcoin mining facility in china. Overhead power appears to be - 240/400V on bare, exposed busbars. Some places have exposed busbars, especially things like cranes in high-bays, but this is for some significant power distribution - I'm not sure if this sort of thing would be allowed in the states. China color code: A - Yellow B - Green (WTF?!) C - Red Neutral - Blue Ground - Green/Yellow Someone in the OSHA Reddit this was from said those bars were rated to carry around 3200A (seems high to me). So you might have a tremendous amount of fault energy available there should something go wrong at the bus or at one of the connections tapping off from the bus, unless each tap has something like a fuse that can handle big fault currents. There was another photo that showed two sets of two meters reading 240V, 3200A. Only 2.2 megawatts. (400*3200*1.73) Three-Phase fucked around with this message at 23:11 on Jun 9, 2015 |
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Jun 9, 2015 23:01
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CampingCarl posted:That bitcoin mine did add some safety measures. One of the things here - if you were using a real piece of switchgear instead of this cobbled-together (but arguably clean) approach of having the breakers and busbars on a metal frame, you'd probably have better bracing of the busbars themselves. When you buy a piece of switchgear, it usually has a maximum fault current rating. Like 100,000 amps. What that means is when you have a short circuit somewhere, as long as (for a short duration) you have under 100,000 amps flowing into the fault, the gear will physically keep itself together. The stresses there aren't from heat - it's from the massive magnetic fields that can be generated during the fault - fields that can tear apart equipment, warp busbars, etceteras. The busses and cables have to be secured to handle the forces from these faults. Purpose-built, properly engineered equipment, is designed to withstand the magnetic forces during a fault. They are specified based in part off the power supply - how much power in can send into a "bolted fault" (like a metal rod falling between two phases - a fault with very low impedance and extremely high current flow.) Equipment that is just thrown together may not be able to handle a fault should it occur. However, it is arguably orders of magnitude cheaper in a place where human life is far, far cheaper. (Circuit breakers themselves are similar - they have a maximum interruption rating, say 10,000 amps for a tiny 20A breaker. If the source can pump out more than the interruption rating of the breaker in a fault, the breaker may fail catastrophically when trying to interrupt the fault.) TL;DR VERSION: Just watch this. Like that, but with the metal busbars. https://www.youtube.com/watch?v=3dckmSgp1nw Three-Phase fucked around with this message at 23:37 on Jun 11, 2015 |
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Jun 11, 2015 23:33
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EMILY BLUNTS posted:could it be strong enough to pull all of the mining boxes off the shelf? I doubt it.
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Jun 12, 2015 02:41
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