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Lightning rod missing on building

Discussion in 'Electrical Engineering' started by Skybuck Flying, Jun 6, 2011.

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  1. There was a show on television called: "Is it possible ?" it was on the
    "Discovery Channel".

    There was a man, a doctor, who had electricity as a hobby.

    The called him: "Doctor (Dr.) Electric"

    He was standing in a cage around his body. The electric beam struck the
    cage. He remained unharmed. Perhaps he was lucky, perhaps not.

    Then he went into a pool with tinfoil on his head.

    His head was above the water.

    He had a glove of metal and a wire from the glove going into the water.

    The electric beam hit the glove and he remained unharmed.

    The electric beam was repositioned to hit his tinfoil hat while he was in
    the water.

    He again remained unharmed.

    To lessons learned:

    1. Electricity/electric beams/lightning follows the fastest/least resistent
    path to earth/ground.

    2. Electricity/electric beams/lightning dispearses (distributes) in water.
    (each h2o molecule forms a path)

    (Only the first few centimeters are dangerous in water)

    Doctor Electric was very convincing... though they did throw some kind of
    cable into the water.

    And they did not show the entire cage... so there are still some doubts.

    Apperently there was a cable going back to the Teslacoil/Telsalightning
    device.

    I remain a bit skeptical but it was cool and interesting, I kept watching to
    the very end until they showed that part/what would happen.

    His name is well deserved "Doctor Electric !" ;) =D

    Now if he could only shoot beams from his hands then that would be totally
    awesome ! ;) =D

    Bye,
    Skybuck.
     
  2. Don Kelly

    Don Kelly Guest

    "Skybuck Flying" wrote in message

    There was a show on television called: "Is it possible ?" it was on the
    "Discovery Channel".

    There was a man, a doctor, who had electricity as a hobby.

    The called him: "Doctor (Dr.) Electric"

    He was standing in a cage around his body. The electric beam struck the
    cage. He remained unharmed. Perhaps he was lucky, perhaps not.

    ---------------
    It's called a "Faraday cage"- it does provide protection- that is why you
    are safe inside your car when a power line falls on it .
    -------------------------

    Then he went into a pool with tinfoil on his head.

    His head was above the water.

    He had a glove of metal and a wire from the glove going into the water.

    The electric beam hit the glove and he remained unharmed.

    The electric beam was repositioned to hit his tinfoil hat while he was in
    the water.

    He again remained unharmed.
    -----------
    It appears that he was using a Tesla coil- lots of spectacular effects but
    the current is generally so low that no harm is done and the frequency is
    high enough that no shock is felt-Tesla used it on stage to "show" that AC
    was "perfectly safe" Having arcs and corona from extremities is commonly
    done.
    -----------------------------
    To lessons learned:

    1. Electricity/electric beams/lightning follows the fastest/least resistent
    path to earth/ground.
    -------------------------------------------------
    Not necessarily-the lightning stepped leader development and local
    breakdown dictates the path and this path can be pretty indirect and
    unpredictable. In this way, lightning makes its own least resistant path
    during the development of the stepped leader
    ----------------------------------------------------
    2. Electricity/electric beams/lightning dispearses (distributes) in water.
    (each h2o molecule forms a path)

    Only the first few centimeters are dangerous in water)
    ----------------------------------------------
    There is dispersal- there is also dispersal in the ground when lightning
    hits a tree.
    If this was real lightning- he would likely be dead. The glove and foil hat
    would probably be vaporized and his body.
    Think how many people have died from 120V devices falling into their
    bathtub- voltages and currents involved are miniscule compared to lightning.
    Don't count on only the first few centimeters being dangerous.

    I'm sure it was a nice show but don't try to draw conclusions about
    lightning from it.


    Don Kelly
    cross out to reply
     
  3. Yeah,

    I had a feeling we weren't getting the whole thruth from that show.

    I have seen more "unthruths" from the discovery channel.

    So it's a bit of an "amaturistic" channel I guess.

    Bye,
    Skybuck ;)
     
  4. Oh,

    By the way...

    There was one more thingy they showed:

    Eletricity blowing up a pompkin.

    How do you explain that mister ?! ;) =D

    Bye,
    Skybuck =D
     
  5. Daar heeft geluk niets mee te maken, gek.
    Had je maar moeten opletten op school: kooi van Faraday.
     
  6. Ifrit

    Ifrit Guest

    NL.wetenschap geen EN.wetenschap

    (gewoon Nederlands blijven schrijven dus)
     
  7. Don Kelly

    Don Kelly Guest

    "Androcles" wrote in message

    | Think how many people have died from 120V devices falling into their
    | bathtub- voltages and currents involved are miniscule compared to
    lightning.

    How many?
    Many years ago I ran some tests on a borehole motor/pump unit.
    The motors are filled with distilled water which acts as a lubricant
    for the bearings and the wire used in the windings have a rubberised
    coating). This particular motor had failed a megger test when it was
    in the test tank so I added some detergent to the distilled water and
    ran it. It was still scrapped because one can't drink soapy water
    but it proved that soapy water is an insulator, salt water a conductor.
    ------------------------
    I haven't a count but in the old days of cheap radios without a transformer,
    people sometimes used them on the side of a bathtub and accidents did
    happen. Heaters were also a problem but in both situations one could
    consider it Darwinian selection. This was likely not a UK problem as these
    old radios had 2 prong unpolarized plugs so that there was the possibility
    of a hot chassis.
    Why would you want to drink the water used as a bearing lubricant- with or
    without the soap? If it is distilled, surely you wouldn't want it mixing
    with whatever is being pumped (even potable water ). Could it be that the
    distilled water was contaminated because of a leaky seal?
    Information on the net seems to indicate that detergents actually raise
    conductivity- certainly low conductivity detergents (<50 microSiemens/cm)
    are more conductive than distilled water (<10 microS/cm) so your observed
    result might well be due to another factor such as contamination or the
    absorption of metal ions over time.
    What is needed is a test under proper conditions to measure comparative
    conductivities. A simple but indicative test would be using a pair of clean
    electrodes in distilled,deionized, tap, and soapy, water and comparing
    currents at the same voltage. Going further would require a decent lab.


    Don Kelly
    cross out to reply
     
  8. Don Kelly

    Don Kelly Guest

    "Skybuck Flying" wrote in message

    Oh,

    By the way...

    There was one more thingy they showed:

    Eletricity blowing up a pompkin.

    How do you explain that mister ?! ;) =D

    Bye,
    Skybuck =D
    --------------------------
    Let's see, 1ma at 1MV is 1000 watts- make some steam- it won't be an
    instantaneous explosion but it would be faster than it would be in boiling a
    cup of water. However, I don't know just what apparatus was used- some that
    is used in movies is pretty impressive.

    Don Kelly
    cross out to reply
     
  9. Don Kelly

    Don Kelly Guest

    "Androcles" wrote in message

    | "Androcles" wrote in message |
    |
    | || Think how many people have died from 120V devices falling into their
    || bathtub- voltages and currents involved are miniscule compared to
    | lightning.
    |
    | How many?
    | Many years ago I ran some tests on a borehole motor/pump unit.
    | The motors are filled with distilled water which acts as a lubricant
    | for the bearings and the wire used in the windings have a rubberised
    | coating). This particular motor had failed a megger test when it was
    | in the test tank so I added some detergent to the distilled water and
    | ran it. It was still scrapped because one can't drink soapy water
    | but it proved that soapy water is an insulator, salt water a conductor.
    | ------------------------
    | I haven't a count but in the old days of cheap radios without a
    transformer,
    | people sometimes used them on the side of a bathtub and accidents did
    | happen. Heaters were also a problem but in both situations one could
    | consider it Darwinian selection. This was likely not a UK problem as these
    | old radios had 2 prong unpolarized plugs so that there was the possibility
    | of a hot chassis.
    | Why would you want to drink the water used as a bearing lubricant- with or
    | without the soap?

    Would you rather drink oil?
    http://www.alibaba.com/product-tp/112216653/Submersible_Oil_Filled_Motor_For_4/showimage.html

    You can't draw water more than 30 feet high, you have to push it from
    below. That means the pump and the motor have to be submersed or
    else you have a very long rotating shaft between motor and pump.
    For drinking water there is a risk of contamination with an oil or grease
    filled sleeve bearing so the motor is water filled instead.



    | If it is distilled, surely you wouldn't want it mixing
    | with whatever is being pumped (even potable water ). Could it be that the
    | distilled water was contaminated because of a leaky seal?
    | Information on the net seems to indicate that detergents actually raise
    | conductivity- certainly low conductivity detergents (<50 microSiemens/cm)
    | are more conductive than distilled water (<10 microS/cm) so your observed
    | result might well be due to another factor such as contamination or the
    | absorption of metal ions over time.
    | What is needed is a test under proper conditions to measure comparative
    | conductivities. A simple but indicative test would be using a pair of
    clean
    | electrodes in distilled,deionized, tap, and soapy, water and comparing
    | currents at the same voltage. Going further would require a decent lab.
    |
    I didn't go that far, I just used a megger. Kitchen science is enough to
    show a battery and a light bulb can be connected through salt water
    (bubbles of hydrogen and oxygen can be collected) but not distilled
    water. I live in a hard water area, the chalk downs of Kent, and what
    I measured was a fall in conductivity when detergent was added.
    I suspect that the number of bathroom deaths is more Hollywood myth
    than fact, although I have heard of bath salts but never used them.

    Yes, I am familiar with the submersible pumps used in deep wells ( as well
    as the limits of atmospheric pressure on drawing water).
    However, the contamination problem in the case of your hard water well is
    reversed- the hard water can contaminate the distilled water. Now, why is
    the water hard? Dissolved minerals. This implies ions and higher
    conductivity.
    See:

    http://www.globalw.com/support/hardness.html

    So adding a detergent in this case could reduce conductivity but that is
    not the case with soft water.

    The bathroom deaths is not a Hollywood scheme( although overblown by
    Hollywood)- but due to a combination of stupidity and cheapness and lack of
    ground fault protection. It may be have been rare but not out of the
    question. Haven't tried it personally- but in any case, the plumbing is in
    plastic pipes so it provides a poor ground.
    I used to have a humidifier that was basically a pot of water with two
    electrodes about an inch apart- it worked nicely and a bit of salt would
    increase the action.

    Don Kelly
    cross out to reply
     
  10. "Max Doorrijhoogte" wrote in message

    "
    Daar heeft geluk niets mee te maken, gek.
    Had je maar moeten opletten op school: kooi van Faraday.
    "

    Dat weet ik alang stomme lul.

    Ik blijf erbij dat het geluk hebben is.

    Een enkel straaltje er tussen door en je bent dood.

    Herhaal die fokking proef maar eens 1 miljard keer, en dan wet ik voor 1
    cent dat je dood gaat vanwege iets heeeeel bijzonders en raaaarrss..

    Ga nou niet doen als het universum niet een beetje gek is ! ;) =D

    En ja maar denken dat alles altijd precies hetzelfde gaat he ! nou moooooooi
    niet dus ! ;) =D

    Doei,
    Skybuck.
     
  11. Niet gehinderd door enige kennis van zaken...jouw mening gaat boven
    wetenschap..... heerlijke humor!
     
  12. Don Kelly

    Don Kelly Guest

    "Androcles" wrote in message

    -----
    and prior to that time, the only electrical device most people had was a
    light bulb. Some had motors but there was no need for these in a bathroom or
    kitchen.
    ------------------------
    And the drain was bare metal- connected to the plumbing which was likely to
    be cast iron or even copper- ground path existed.
    ------------------------------
    and has done in many- I had to deal with a situation- it appeared that the
    victim touched a toaster and a refrigerator (with no safety ground) at the
    same time. 120VAC does it- not as fast as 240V but, because you have worked
    with 240V -don't dismiss the "measly 120V" hazards.
    --------------------------------------
    Now you are calling on Hollywood. By the way, Edison proposed AC for the
    electric chair- and it was accepted by the state- he wanted to show that it
    was dangerous- the last thing he wanted was to have people see any dangers
    with DC- see the Edison-Tesla "wars".
    ------------------------------
    Maybe times were more innocent way back when.

    ========================================
    Oh sure, that was before Catholic priests were paedophiles - or
    before we naively thought they'd never do such as thing as
    molest a child.


    Some more info here: http://tinyurl.com/4xnlk2o
    ( Journal of the American Medical Association)


    Abstract:

    From 1979 to 1982, in the United States, at least 95 persons were
    electrocuted in bathtubs; 66% of the deaths occurred during the winter
    and spring. Children younger than 5 years had the greatest mortality
    rate, and hair dryers were responsible for 60% of the deaths. Until
    electric appliances used in bathrooms are made safer, the appliances
    should be disconnected when not in use, not used in wet bathtubs, and
    kept away from children.

    End quote.

    There is a link to a PDF with the full text toward the right hand
    side.
    ============================================
    No mention of the percentage of suicides and a call for appliances
    to be safer! In Britain there are no normal sockets permitted, the
    light switch is ceiling mounted and operated by a pull cord and
    the switch for the electric shower is outside the bathroom. A
    lower voltage shaver socket was permitted years ago but I've
    never seen one. Possibly they exist in hotels.
    But all this completely misses the point.
    How does the current pass through a human body, insulated by the
    vitreous coating, from the hair dryer to the drain ?
    ----------
    The nice shiny conductive ring that fits inside the drain opening and
    connects to the plumbing.
    --------------------
    I mean really, a bird can alight on overhead power lines and be
    unharmed, that's no different to dropping the hair dryer into the
    water in the bath tub when your butt is sitting there. Unless the
    bird or you are part of the circuit nothing will happen.
    ----------

    The situation is different now- GFCI devices are mandatory in bathrooms,
    Prior to this shaver outlets had isolating transformers. Also bathtubs are
    mostly fiberglass and the plumbing lines are plastic so the tub and sink are
    isolated.
    In that case there is no good parallel path to ground.
    By the way, note that birds (particularly larger ones) do not sit on EHV
    transmission lines - they don't care for corona discharges from feathers and
    beaks- this has nothing to do with the bathtub situation as it was and
    little more to do with it as it is- there is no path other than a lot of air
    to anything else.

    Don Kelly
    cross out to reply
     
  13. Nee ook voor jou geldt, gebaseerd op ervaring.

    Mensen denken het allemaal zo goed te weten... maar dat is helemaal niet zo.

    Vraag je zelf maar eens af waarom al die vliegtuigen toch steeds blijven
    crashen...

    Ze wisten het allemaal toch zo goed ?! ;) =D

    Nou ik heb inmiddels genoeg stommiteiten gezien in vliegtuig ontwerpen
    hoor... ik stap er mooi niet in... never ! ;) =D

    En dan zwijg ik nog over toevallige samenloop van omstandigheden die jij
    niet voor mogelijk houdt ! ;) =D

    Bijvoorbeeld:

    Wat dacht je van een vogeltje die over jou faraday cage heen vliegt en even
    een plasje maakt !

    Daar ga je dan ! Dood ! Wees gegroet marie vol van genade de heer zij met U
    ! ;) =D

    Doei,
    Skybuck ;) =D
     
  14. In my experience, 100% of bathtubs have drains having metal parts that
    get exposed to water as soon as a liter of water gets into the bathtub.

    And, in older houses and even modern ones in a few older union-town
    cities, the drain pipe is often metal. If I build a house in Chicago or
    Philadelphia nowadays, its toilets need to dump into sewer line via
    metal pipe.
     
  15. Tja als je de omstandigheden van het experiment verandert, kunnen ook
    de uitkomsten veranderen.
    Maar vogels urineren niet voldoende voor deze stelling, helaas.
    En dan nog hoort dit niet thuis in nl.politiek
     
  16. Ja je kunt wel blijven doorzeiken, maar feit blijft dat die gast helemaal
    niet de omstandigheden in de hand had ! ;) :)

    Die gast die stond gewoon buiten ! ;) :)

    En dat is het hele punt ! ;)

    En of een vogeltje nou wel of niet genoeg plast doet helemaal niet ter zake,
    voor hetzelfde geld landt die op de kooi en pikt hij je in je gezicht en
    maakt
    daarmee een verbinding met jou en dan is het game over ! ;) =D

    Doei,
    Skybuck.
     
  17. "The Ghost In The Machine" wrote in message

    "
    UP YOURS MORONIC !
    TGITM
    "

    Try google translate lol, and post it here if you have any further doubts or
    question about what I wrote ! ;)

    It might actually be interesting for you ! ;) =D

    Bye,
    Skybuck =D
     
  18. Or in this case, what he wrote... lol :)

    Bye,
    Skybuck =D
     
  19. trol
     
  20. Many of those lines are 2300 or 4600V, and live trees are usually not
    good insulators.
     
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