ucw458 Posted December 11, 2009 Report Share Posted December 11, 2009 http://www.youtube.com/watch?v=PHs14ZTo96M This is the type of breaker they were racking and the safe way to do it.http://www.youtube.com/watch?v=FUEAbYl0NbU&NR=1 Link to comment Share on other sites More sharing options...
Guest Posted December 11, 2009 Report Share Posted December 11, 2009 Wonder if that dude got burned? In college I worked at a hospital, these engineering guy I knew was doing some maitenance and he got hit with a a cachillion volts, instantly cooked his arms, chest and hair. He was in the ICU for weeks, needed skin graphs and a bunch of surgery. I think he lost some fingers. Link to comment Share on other sites More sharing options...
Fanta Posted December 11, 2009 Report Share Posted December 11, 2009 Wonder if that dude got burned? In college I worked at a hospital, these engineering guy I knew was doing some maitenance and he got hit with a a cachillion volts, instantly cooked his arms, chest and hair. He was in the ICU for weeks, needed skin graphs and a bunch of surgery. I think he lost some fingers. when it erupts and you see a bright white shiny immediately to the right of the door and moves upwards, then you see flames in the back of the room? yeah thats the guy that got nailed. Link to comment Share on other sites More sharing options...
ucw458 Posted December 11, 2009 Author Report Share Posted December 11, 2009 He very well could have died from that blast. Those guys weren't wearing the required safety suits to protect them from the blast. The guys in this video were and see how bad it hit them even with safety gear on. http://www.youtube.com/watch?v=h10ALIpD0R4 Link to comment Share on other sites More sharing options...
Cobalt60 Posted December 11, 2009 Report Share Posted December 11, 2009 http://www.youtube.com/watch?v=qEG-1iYpgKU&feature=related Link to comment Share on other sites More sharing options...
Guest Posted December 11, 2009 Report Share Posted December 11, 2009 Well at least those guys got to walk away. Link to comment Share on other sites More sharing options...
BrazilBoy Posted December 11, 2009 Report Share Posted December 11, 2009 Well at least those guys got to limp away.Fixed it for ya... when I was 16 I just installed my HEI Accell unit on my Z28..I was setting the timing when I touched it on the worng spot I tossed me back...I was a bit of wreck the rest of the day..lol Link to comment Share on other sites More sharing options...
ucw458 Posted December 11, 2009 Author Report Share Posted December 11, 2009 (edited) when I was 16 I just installed my HEI Accell unit on my Z28..I was setting the timing when I touched it on the worng spot I tossed me back...I was a bit of wreck the rest of the day..lol Same here, I had an MSD 6A box on my V8 ford. It was idling and I didn't know it had a bad coil wire. One hand on the fender the other touched the distributor and I got hit by the MSD through one arm, across my chest, and out the other arm. I let out a yell and jumped back about 6 feet. I had to go inside and sit down after that. My chest hurt for awhile. Edited December 11, 2009 by ucw458 Link to comment Share on other sites More sharing options...
Guest Posted December 11, 2009 Report Share Posted December 11, 2009 Same here, I had an MSD 6A box on my V8 ford. It was idling and I didn't know it had a bad plug wire. One hand on the fender the other touched the distributor and I got hit by the MSD through one arm, across my chest, and out the other arm. I let out a yell and jumped back about 6 feet. I had to go inside and sit down after that. My chest hurt for awhile. lol Link to comment Share on other sites More sharing options...
ucw458 Posted December 11, 2009 Author Report Share Posted December 11, 2009 Same here, I had an MSD 6A box on my V8 ford. It was idling and I didn't know it had a bad plug wire. One hand on the fender the other touched the distributor and I got hit by the MSD through one arm, across my chest, and out the other arm. I let out a yell and jumped back about 6 feet. I had to go inside and sit down after that. My chest hurt for awhile. lol Yeah at 900 rpm divide by half because it's a 4 stroke then multiply by the # of cylinders, 8, then multiply again by 3 because at that rpm the msd fires 3 times per cylinder, then divide by 60 for 60 seconds in a minute and you get 180. So in that second I got hit by the MSD I got zapped almost 180 times by 48,000 volts at almost half an amp. It hurt. If it had been a full amp of current and not almost a half amp it would have stopped my heart. Link to comment Share on other sites More sharing options...
Technology Posted December 11, 2009 Report Share Posted December 11, 2009 Yeah at 900 rpm divide by half because it's a 4 stroke then multiply by the # of cylinders, 8, then multiply again by 3 because at that rpm the msd fires 3 times per cylinder, then divide by 60 for 60 seconds in a minute and you get 180. So in that second I got hit by the MSD I got zapped almost 180 times by 48,000 volts at almost half an amp. It hurt. If it had been a full amp of current and not almost a half amp it would have stopped my heart. I'm going to go ahead and call you out on that math. You're wrong, but I'm not going to prove it because it's too late. Link to comment Share on other sites More sharing options...
ucw458 Posted December 11, 2009 Author Report Share Posted December 11, 2009 Yeah at 900 rpm divide by half because it's a 4 stroke then multiply by the # of cylinders, 8, then multiply again by 3 because at that rpm the msd fires 3 times per cylinder, then divide by 60 for 60 seconds in a minute and you get 180. So in that second I got hit by the MSD I got zapped almost 180 times by 48,000 volts at almost half an amp. It hurt. If it had been a full amp of current and not almost a half amp it would have stopped my heart. I'm going to go ahead and call you out on that math. You're wrong, but I'm not going to prove it because it's too late. If it's too late for you to try to prove I'm wrong then it's too late for you to realize my math is correct. Especially since I spelled it out. But here I'll spell it out in more detail. It idles at 900 rpm. 4 stroke motors take 2 revolutions to fire all the cylinders. So divide 900 by 2 and you get 450. 450 times a minute the engine fires all cylinders. 8 cylinders right, so 450 x 8 = 3600 that's 3600 sparks per minute at 900 rpm. The MSD fires 3 times per cylinder at that rpm. It says so in the MSD manual. So 3600 x 3 = 10800 With the MSD that's 10,800 sparks per minute at 900 RPM. Now RPM is Revolutions Per Minute so you divide 10,800 by 60 to get 180 sparks per second. Now the coil wire was the one that was damaged so that's the one that got me. So every time the coil fired I got hit. Link to comment Share on other sites More sharing options...
craig87 Posted December 12, 2009 Report Share Posted December 12, 2009 The first hybrid class i ever went to the instructor said the most important thing to remember is.when servicing a hybrid always have some one watching you while disableing the system If the guy is crappie flopping he touched the a/c side if he is perfectly still he touched the d/c side. without an ammeter clamped on your arm I would have to say you didn't see half an amp unless you had the coil wire in your hand and no other viable lower resistance path to ground. You also wont see the true hit from the coil due to the coil that is grounded (by you) will not fully saturate. Scope an ignition with a shorted cylinder fire line goes wayyyy down usually under 1 kv. now if you had an open wire that you grouded you can get 30kv or so. did you kill the motor? I've been hit by almost every style of ignition system out there and will state that points hurt the most. I am not in any way shape of form saying it doesn't suck ever cut 110 live with uninsulated pliers. that sucks a little. Link to comment Share on other sites More sharing options...
Turborusty Posted December 12, 2009 Report Share Posted December 12, 2009 When I was about 8, my dad told me to stick my finger in the plug hole of a magneto while he gave it a spin. @$$hole! Turborusty Link to comment Share on other sites More sharing options...
ucw458 Posted December 12, 2009 Author Report Share Posted December 12, 2009 The first hybrid class i ever went to the instructor said the most important thing to remember is.when servicing a hybrid always have some one watching you while disableing the system If the guy is crappie flopping he touched the a/c side if he is perfectly still he touched the d/c side. without an ammeter clamped on your arm I would have to say you didn't see half an amp unless you had the coil wire in your hand and no other viable lower resistance path to ground. You also wont see the true hit from the coil due to the coil that is grounded (by you) will not fully saturate. Scope an ignition with a shorted cylinder fire line goes wayyyy down usually under 1 kv. now if you had an open wire that you grouded you can get 30kv or so. did you kill the motor? I've been hit by almost every style of ignition system out there and will state that points hurt the most. I am not in any way shape of form saying it doesn't suck ever cut 110 live with uninsulated pliers. that sucks a little. Yeah due to resistance I probably didn't get the full load. The engine may have stumbled but I really wasn't paying attention to the engine at the time. It was still running when I regained my senses. It's funny you say points are worse. I found points to be tame compared to msd but that's just my experience. I wonder how many people are reading this and thinking, what are points? Yeah I've done uninsulated pliers on 110v, sucks when you think the power is off and it's not. I had an old metal case batt charger that worked just fine but something was loose inside and every so often the case would get electrified and when you went to pick it up it zaped you with 110v When I was about 8, my dad told me to stick my finger in the plug hole of a magneto while he gave it a spin. @$$hole!Turborusty ROFL I'm soooo gonna do that if I ever have a kid. Thanks for the tip. Link to comment Share on other sites More sharing options...
SQF Posted December 12, 2009 Report Share Posted December 12, 2009 When I was 8 I wizzed on an electric fence by mistake. Then again when I was 34 I put my tongue one the "hellbox" used to electrically initiate blasting caps. Neither was a good move. One of them was when I should have known better...... Link to comment Share on other sites More sharing options...
dmyers151 Posted December 12, 2009 Report Share Posted December 12, 2009 (edited) That arc flash crap is no joke man. We do surveys and calcs on that stuff at work from time to time. There's a whole booklet and stuff about catagories of clothing required to work on panels based on arc flash rating, it's crazy. I don't remember the specifics cuz I'm the mechanical guy, not electrical. But I remember our electrical guy saying something about it only taking 1/4 cycle AC to flash as bad as the first video. That guy most likely died or had his clothing fuse to his body. Not only is there extremely intense heat, but also a great deal of pressure, as if a bomb went off. Edited December 12, 2009 by dmyers151 Link to comment Share on other sites More sharing options...
Cobalt60 Posted December 12, 2009 Report Share Posted December 12, 2009 (edited) I fix cameras for a living. Cameras have "flash" capacitors in them, which are typically rated at about 300V. From time to time, us camera techs get shocked. And from time to time, we short out that cap, which results in a pretty loud bang, Id say louder than popping a bag full of air. Well, before I ever worked on cameras, I did get shocked by a spark plug. Id say camera caps are worse. If you dont believe me, give it a try. As for the math on the amps thing, heres a quick point. Say you have a 12V battery that can do 600 cranking amps. That means its absolute max output is 7200W. Now, if you are putting out 48000 volts, 7200W would mean your amps is only 0.15 As far as how many times per second you got shocked, this is how a switched mode power supply works, as well as a PWM. If you get shocked 180 times per second at 48k volts and 0.15A, but also 180 times per second there is no shocking going on, and the length of time of the "on" cycle equals the "off" cycle, in other words a 50% duty cycle: 1/2V x 1/2A = total power, so 1/2 of 48000 volts x 1/2 of 0.15 amps, = 1800W, the equivalent of 24000V and 0.075A. This is all assuming the battery is putting out cranking amps just to provide spark (which its not, as well as a 50% duty cycle (which probably isnt really realistic). Overall though, Id say it is very little amps, my best guess would be 0.05A tops -Chris P Edited December 12, 2009 by Cobalt60 Link to comment Share on other sites More sharing options...
ucw458 Posted December 12, 2009 Author Report Share Posted December 12, 2009 That guy most likely died or had his clothing fuse to his body. Not only is there extremely intense heat, but also a great deal of pressure, as if a bomb went off. Definatly pressure, that stuff is extremely dangerous. My moms neighborhood has underground transformers. One day one of the 13k lines feeding a main transformer shorted and blew. It shot the cable out of the conduit and into the underground transformer vault. It also blew the cap off the vault, it landed 20 feet away. The cap was a 6 foot by 6 foot by 1 foot thick concrete slab with a manhole cover in the center. It sounded like a bomb went off when that blew. Thankfully no one was driving on that part of the street when it blew. Basically if a line short has enough power to remove a concrete slab that breaker short has enough power to kill instantly. Link to comment Share on other sites More sharing options...
Chad Posted December 12, 2009 Report Share Posted December 12, 2009 You guys realize the spark discharge output is not a true square wave right, it's the instantanious discharge of a suspended magnetic field that creates the high volt output, but the high voltage part of that cycle is extremely brief part of the entire discharge. This instantanious voltage is called "back EMF" (google if it you want a better deffinition that I can provide) Once that field has begun to colapse, most of the discharge (output voltage) is the same voltage was that you put into it. If you put in a 1 hz square wave of 12 volts DC, the output will be mostly 1 hz square wave of 12 volts DC out, the initial high voltage spike will still be extremely brief, like 1/1,000,000 of a second. Almost all of the current is discharged at 12 volts (or what ever it was steped-up to), not during the brief 40,000 volt field colapse event. Also, most coils are step up transformers, when you step up the voltage, you step down the current at the same ratio. Coil discharges are a lot like static shocks, those can be 5000-50,000 volts, but not much current, and extremely breif. A 120 to 240 volt AC shock is far more likely to kill you than a coil discharge, it's the current and duration that kills you. Link to comment Share on other sites More sharing options...
v8starion Posted December 12, 2009 Report Share Posted December 12, 2009 When I was about 8, my dad told me to stick my finger in the plug hole of a magneto while he gave it a spin. @$$hole! I had that pulled on me aswell. A Mag has a hell of a bite. Link to comment Share on other sites More sharing options...
craig87 Posted December 13, 2009 Report Share Posted December 13, 2009 I will play with a flash capacitor if you touch the flyback coil on a crt tube, I shut my arm off for a hour with one of those . its amazing how much stray voltage the body can handle when it doesn't cross the chest. chad is right about the discharge of a coil isn't square and will be steped up greatly depending on saturation time and turn ratio many times in excess of 20 kv for a few Ms. Link to comment Share on other sites More sharing options...
Cobalt60 Posted December 13, 2009 Report Share Posted December 13, 2009 I will play with a flash capacitor if you touch the flyback coil on a crt tube Heh Im all set with that. Brings up something though. I have an old school bench power supply. When I received it I had to open it up to get some loose metal out. Inside is a capacitor the size of a soda can. The power supply is rated 36V / 5A. think that cap is dangerous? Its primary purpose is to smooth out any ripples left from the AC mains. Link to comment Share on other sites More sharing options...
ucw458 Posted December 13, 2009 Author Report Share Posted December 13, 2009 Heh, I was working on an AC condenser and I had my mind on other things so I made a stupid mistake. Push in the contactors and the compressor would hum but didn't run. First thing to check is the run capacitor. This unit had an 85mfd run cap and a hard start kit which is basically a 1000mfd booster/start cap and relay. Both caps are connected to the same terminal and I have to unplug both caps to test them with my meter. So I grab the wire terminal to disconnect it and ZAP OWWWWWWWWW. In my hurry I forgot to disconnect the power to the condenser. btw it's powered by 240 volt AC single phase. Thankfully I only touched one side. Link to comment Share on other sites More sharing options...
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