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Thread: Bugger...

  1. #31
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    Quote Originally Posted by buffo View Post
    Anyone else ever try stripping the insulation off a lamp cord while it was still plugged into the wall? With your teeth?
    American power systems are too puny to turn that into a *really* bad day. Us european types with our 230 (or, in the UK prior to the late 90s, 240) volt power can tell you how it feels to take a belt off that...

  2. #32
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    Oh I know - I've been hit with a lot more than just 120. But not in my mouth! (Consider the combination of near-perfect conductivity plus extreme nerve sensitivity...) Yeah, that was a bad day for sure.

    But on the higher voltage side, a long time ago I was building a small DC power supply, and I stupidly hooked the transformer up backwards, so instead of taking the 120VAC down to around 6 volts or so, it stepped it way the hell up to around 2400VAC or so. Which, of course, blew straight through the bridge rectifier I had, yielding high voltage AC at the output.

    So imagine my confusion when my DC meter isn't reading anything at the output. Since it's all low voltage, I don't mind poking my hands around in there - nothing to be afraid of, right? ZAP! *aaaaaaaaaAAAAAOUCH!* (Yes, really careless, but I was in my 20's and thus invincible.)

    That thing embedded itself in the drywall across the room. (Me throwing it was completely involuntary.) Once again, my wife was not amused. Sigh... "Sorry honey. I'll go down to the hardware store to get some spackle as soon as the tremors in my hands go away." (They ended up lasting for the better part of the day.)

    Adam

  3. #33
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    I must taken several hundred shocks in my life, the first one I remember I was about 4 years old when I poked a length of Mechano (erector set) in to the bar of an electric heater (240v goodness). I've taken HV DC shocks, NST shocks, electric fence shocks, large tesla coil secondary shocks, strobe capacitor shocks but to this day nothing has been more painfull than the shocks from the 5 or so I've had from high energy ignition systems (high boost Audi turbos, the 80s, £120 for a set of spark plugs back then, that would be burned away in 5000 miles - sledge hammer/nut).

    Once they were a couple of years old they would flashover 2" to your hand or any conductive grounded thing that came near the ignition system, then exit with another arc from your knees to the bumper, jeeez. It's probably the pulsed nature of the shock more than anything but its like being hit with a bat repeatedly very fast, burns too.

    ... and Adam, +1 for the expletives, I think I've invented a few new ones here n there.
    http://img62.imageshack.us/img62/3985/laser.gif

    Doc's website

    The Health and Safety Act 1971

    Recklessly interfering with Darwin’s natural selection process, thereby extending the life cycle of dim-witted ignorami; thus perpetuating and magnifying the danger to us all, by enabling them to breed and walk amongst us, our children and loved ones.





  4. #34
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    Ignition systems are bad, but NOTHING comes close to a belt from a high impedance node in a powerful (1KW+) VHF rf amplifier.

    Thing it, it doesn't need an exit, your body will serve as an aerial quite happily, and it burns deeply, and takes forever to heal.

    Really very unpleasant, been there, done that, accidentally getting across two phases (in 230/400V land) is nothing in comparison (But the RF is less likely to kill you).

    Regards, Dan.

  5. #35
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    Quote Originally Posted by DMills View Post
    Ignition systems are bad, but NOTHING comes close to a belt from a high impedance node in a powerful (1KW+) VHF rf amplifier.

    Thing it, it doesn't need an exit, your body will serve as an aerial quite happily, and it burns deeply, and takes forever to heal.

    Really very unpleasant, been there, done that, accidentally getting across two phases (in 230/400V land) is nothing in comparison (But the RF is less likely to kill you).

    Regards, Dan.
    Yeah, I've had a couple of RF burns from grounded objects when stood 6' from my tesla coil but didn't feel a shock, just the burn and the awful smell.

    It worries me when I see fools on youtube doing the lightning from the fingertips trick. Aside from the risk of a streamer connecting one to the tank circuit or other sources of dangerous current; It is now known (last 10 years or so) that the skin effect (in the high khz region at least) is not sufficent protection. Skeletal joint fulguration and nerve damage due to internal RF arcing and/or heating has been proven.

    Scares the shit out of me high power RF.

    Ian
    http://img62.imageshack.us/img62/3985/laser.gif

    Doc's website

    The Health and Safety Act 1971

    Recklessly interfering with Darwin’s natural selection process, thereby extending the life cycle of dim-witted ignorami; thus perpetuating and magnifying the danger to us all, by enabling them to breed and walk amongst us, our children and loved ones.





  6. #36
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    Quote Originally Posted by DMills View Post
    (But the RF is less likely to kill you).
    In the short term anyway.....

  7. #37
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    You really should have a grounded electrode forming an incomplete turn just above the primary coil, makes a streamer taking out your driver (or arcing to the secondary winding near the bottom) much less likely. More critical if doing the solid state drive thing, but a good idea anyway.

    Yea, lots of ways to screw up with a tesla coil.

    Regards, Dan.

  8. #38
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    Feb 2009
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    Talking Self inflicted DARWIN AWARDS

    Quote Originally Posted by heroic View Post
    If you are working with a soldering iron, it is vitally important NOT to try to catch it when your elbow knocks it out of its stand.

    Please don't ask me how I learned this (age 11).
    I had a simmlar steep learning curve when i was arround the same age complete with broiled and blackened fingertips and an afternoon up at the hospitals Accident and Emergency department.

    Needless to say i now do all potentially harmful work STANDING UP knowing i can jump back and asses a bad situation before i intervene.

    The next lesson was learned at the age of 12 when building a 5Kv HeNe Power supply seing how far i could draw off arcs, Entry and exit burns are fun!!! Especially when you have one on each hand and can trace the flow of Current across your chest...

    I'm quite frankly Amazed that i have made it in to my mid 20's

    Shocks of FAME: Age of 17 took 15KV at 30mA through my earlobe and out my right foot,
    Five years ago i received a 100KV 250ma 10 pulse per second DC shock
    from a malfunctioning portable x-ray machine that landed me unconscious and in cardiac arrest, working at the hospital has it's percs
    Last edited by matt_man10; 06-24-2010 at 17:17. Reason: felt obliged to willy wave...
    The mind is like a parachute, It doesn't work if it's not open...

  9. #39
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    Quote Originally Posted by norty303 View Post
    Had to stop play halfway through fitting my first 445 into my first projector today because I snapped my M3 tap off in one of the shimming blocks for the 445 mount....


    Arsebiscuits. And the missus and nipper gets back tomorrow so it puts paid for any further work until next weekend now.... double arsebiscuits





    Just had to get that off my chest.

    Thank you
    if it is any consolation norty, i have hand tapped about 300 holes in three days, and I have about 100 holes to go tonight
    Pat B

    laserman532 on ebay

    Been there, done that, got the t-shirt & selling it in a garage sale.

  10. #40
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    Taps arrived yesterday, now I just need to find a time when i won't wake the nipper or upset the missus and we might just get some blue light this weekend!

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