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Fluorescents and migraines??

Discussion in 'Electrical Engineering' started by Dean Hoffman, Jan 7, 2008.

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  1. Dean Hoffman

    Dean Hoffman Guest

    http://tinyurl.com/296h8p

    Is there any truth to this article?


    I read another article claiming some of the old American house
    wiring won't handle CFLs. How can that be if CFLs take less amperage
    than incandescents?

    Dean
     
  2. bud--

    bud-- Guest

    Crossposted to sci.engr.lighting
    Does the spectrum cause migranies and "skin eruptions"? I thought
    migraines were flicker rate which should be a non-issue with CFLs.
    I agree
     
  3. I think these might have started from a couple of BBC articles
    last week accompanying short news features on radio/TV.

    http://news.bbc.co.uk/1/hi/health/7167860.stm is an article
    with an alarmist headline and nothing credible to back it up,
    and an explanation near the bottom of how the misunderstanding
    has come about. Basically an alarmist piece of crappy jornalism.

    http://news.bbc.co.uk/1/hi/health/7167860.stm is the other
    article. It's been discussed on the radio and the people
    affected are affected by any bright light including sunlight.

    These are remarkably poor articles, particularly for the BBC,
    which are being picked up and propapated by other parts of the
    media. It's been accompanied radio/TV coverage giving time to
    those who just want to moan about filament lamps being phased
    out.

    There are actually real issues presented by the phasing out
    of filament lamps, but those aren't getting any coverage at
    all, of course.
     
  4. bud--

    bud-- Guest

    CFLs run at high frequency giving high frequency (probably totally
    invisible) flicker. Is the high frequency flicker modulated at 50Hz
    giving a visible flicker? (Just curious.)
    (This is the same link.)
    CFLs shouldn't be brighter than incandescents???

    So you can get migraines from "low intensity of the light" (1st article)
    and other problems from the bright light. And both problems are caused
    by CFLs.

    Does the spectrum of fluorescents cause skin problems as the original
    link claimed?
    It is comforting to know that bad news reporting is not unique to the US.
    Thanks for the further information.
     
  5. No. There could be 100Hz modulation. There is with some
    filament lamps, but no one claims they give migranes.

    You get 50Hz flicker from tubes on old magnetic control
    gear if they are partially rectifying the discharge.
    This can happen with badly manufactured tubes where one
    of the electrodes isn't working well, and tubes in the
    last couple of hours of life when the last bit of emissive
    material is just wearing off one end immediately prior to
    the tube going out. 50Hz flicker is certainly uncomfortable
    to many people, resulting in stress and headaches, and
    I suspect is a trigger for migraines in some people.

    I think it's this effect which has got mixed up with the
    issue of compact fluorescents, although it's impossible
    with electronically ballasted fluorescents used in
    compact fluorescent retrofit lamps.
    Oops, should have been http://news.bbc.co.uk/1/hi/health/7170246.stm
     
  6. The 365 nm triplet is actually a weak feature of the low pressure
    mercury vapor discharge. It is related to the 577-579 nm yellow triplet,
    which is also a strong feature of a high pressure mercery vapor discharge
    but a weak feature of the low pressure one.

    Most fluorescent lamp phosphors do not utilize 365 nm, though the
    usual mid-blue component of triphosphors 3500K and higher does utilize it.

    Also, soda lime glass is nearly enough transparent at least down to 340
    nm. However, not much 310 nm gets through, and I think that is the next
    shorter wavelength significant spectral feature of mercury vapor (another
    triplet in the same series as the 577-579 and 365-366 nm ones).

    Try exposing various fluorescents to a BLB blacklight. My experience is
    that triphosphor ones 3500K and higher glow bright blue, meaning the glass
    passes the UV. Most other fluorescents give little or no reaction,
    indicating that the phosphor does not utilize that wavelength.

    - Don Klipstein ()
     
  7. That sounds long to me for suntanning. Wavelengths longer than about
    330-335 nm or so don't do that much.
    I thik the effective cutoff wavelength is a little longer for windows
    and a little shorter for fluorescent lamps, in part from window glass
    being thicker, and in part from window glass having a slight tinting by
    iron.

    As for fluorescents made specifically for suntanning - I think they
    would use a different glass to pass even shorter wavelengths.
    I don't expect there to be a whole lot because the 365-366 nm triplet is
    a weak feature of the low pressure mercury vapor discharge.

    Some spectral power distribution curves:

    http://ledmuseum.home.att.net/spectra7.htm

    Look for "Trisonic" 6500K (halophosphor) ones, all others noted as
    "dollar store" ones, and compact fluorescents noted as 2700 K, Sylvania
    "white" (halophosphor). The 365-366 nm feature is about half as strong as
    the 404.7 nm one in all of these.

    Two non-phosphor lamps that emit UVC are shown also: A "Water Purifier"
    one and a "UVC" one (though with weak UVC output). The latter also has
    365-366 about half as strong as 404.7, and the former has more 365 (I have
    seen a similar lamp get hotter and have higher mercury vapor pressure -
    that may be the explanation).

    I tried getting the spectral power distribution of a Sylvania F40/350BL.
    (Copying and pasting links is messy with Sylvania's website - I would try
    searching their USA "business" lamp catalog for F40350BLECO 30/CS 1/SKU
    or 24922.)

    The spectral power distribution has the 365-366 nm spike smaller than
    the 404.7 nm one, and there is a little one shown at 310 nm.

    - Don Klipstein ()
     
  8. Guest

    | Does the spectrum cause migranies and "skin eruptions"? I thought
    | migraines were flicker rate which should be a non-issue with CFLs.

    I see CFLs that flicker. Probably very cheap ones. But they exist.

    BTW, I bought an LED flashlight the other day that has a white spectrum
    that does not bother me like other LEDs and all fluorescents and metal
    halides do. And it's a rather bright and well built one. LEDs are now
    looking more like they could be my future efficient lighting method.
     
  9. Guest

    | http://news.bbc.co.uk/1/hi/health/7167860.stm is the other
    | article. It's been discussed on the radio and the people
    | affected are affected by any bright light including sunlight.

    I know I am affected by very bright light due to the brightness. But if
    restricted enough, and that light is fine for me as a task or reading
    light. Fluorescent lights, including CLFs, even when at low brightness,
    can give me a headache within about 20-30 minutes


    | There are actually real issues presented by the phasing out
    | of filament lamps, but those aren't getting any coverage at
    | all, of course.

    Like how many CFLs does it take to keep my ophidian friends warm?
     
  10. Guest

    | CFLs run at high frequency giving high frequency (probably totally
    | invisible) flicker. Is the high frequency flicker modulated at 50Hz
    | giving a visible flicker? (Just curious.)

    If they convert to DC and smooth it first, the answer would be no. Since
    I see flicker from many CFLs, then it must be that not all of them do it.
    FYI, this flicker is not what bothers me.


    | Does the spectrum of fluorescents cause skin problems as the original
    | link claimed?

    What about unfiltered halogens?
     
  11. bud--

    bud-- Guest

    I should have said 100Hz but comments about 50Hz are interesting.
    My guess is the DC drops substantially twice a cycle which should
    produce modulation. But the phosphor persistence would counteract that
    depending on the value of persistence. I hadn't thought about filament
    lamps...
     
  12. Well, both CFLs and linear fluorescent lamps that use high
    frequency electronic ballasts can and do have flicker if the
    DC storage capacitor is nor large enough to prevent 100 Hz
    or 120 Hz modulation of the internal DC link. I have
    measured the flicker on a few CFLs using electronic ballasts
    and plan to publish the data, but have yet not done so.

    CFLs with integral electronic ballasts are much more likely
    to have flicker than linear or compact fluorescent lamps
    using separate ballasts due to the size and cost constraints
    of the ballast in integral CFLs.

    --
    Vic Roberts
    http://www.RobertsResearchInc.com
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.

    This information is provided for educational purposes only.
    It may not be used in any publication or posted on any Web
    site without written permission.
     
  13. Perhaps not so crappy, since integral CFLs can have flicker
    even if they use high frequency electronic ballasts. See my
    other note.
    This is the same link as the first.0
    --
    Vic Roberts
    http://www.RobertsResearchInc.com
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.

    This information is provided for educational purposes only.
    It may not be used in any publication or posted on any Web
    site without written permission.
     

  14. They do smooth the DC - but not enough to remove all the
    100/120 Hz flicker.

    --
    Vic Roberts
    http://www.RobertsResearchInc.com
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.

    This information is provided for educational purposes only.
    It may not be used in any publication or posted on any Web
    site without written permission.
     
  15. Line-powered LEDs can also flicker if the DC link is not
    properly filtered.

    --
    Vic Roberts
    http://www.RobertsResearchInc.com
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.

    This information is provided for educational purposes only.
    It may not be used in any publication or posted on any Web
    site without written permission.
     
  16. TKM

    TKM Guest

    For a paper published some years ago on the UV output of "white" light
    linear fluorescent lamps, we found that there was a substantial UV
    differential between T8 lamps made in Europe and North American produced T8
    lamps. An analysis indicated that the amount of iron in the glass was the
    primary reason. Higher iron content reduces UV output.

    Terry McGowan
     
  17. I agree that the UV output below 390 nm of most general lighting
    fluorescents is low. I was adding data to support my claim as to why it
    is usually low - the low pressure mercury arc does not produce much
    between the 253.7 and 404.7 nm features, and that mid-UVA (specifically
    365-366 nm) passes through most glass and many to most fluorescent lamp
    phosphors (so the glass is usually not the explanation for relative lack
    of mid-UVA and often the phosphor is not).

    - Don Klipstein ()
     
  18. Guest

    | On 9 Jan 2008 05:52:14 GMT, wrote:
    |
    |>
    |>| Does the spectrum cause migranies and "skin eruptions"? I thought
    |>| migraines were flicker rate which should be a non-issue with CFLs.
    |>
    |>I see CFLs that flicker. Probably very cheap ones. But they exist.
    |>
    |>BTW, I bought an LED flashlight the other day that has a white spectrum
    |>that does not bother me like other LEDs and all fluorescents and metal
    |>halides do. And it's a rather bright and well built one. LEDs are now
    |>looking more like they could be my future efficient lighting method.
    |
    | Line-powered LEDs can also flicker if the DC link is not
    | properly filtered.

    No doubt. Maybe one day the lighting industry will figure out how to
    properly smooth out the DC? Hint: it can be done without those big
    capacitors that power supplies of days gone by had. One idea that
    comes to mind is to chop the current with a pulse width varied to
    compensate for the lower frequency component(s) of the ripple.
     
  19. They already know, but it costs more money than most
    consumers want to pay.
    I large number of circuits that have high input power
    factor, low energy storage requirements and low DC ripple
    have been published and/or patented. However, all cost
    money and all dissipate energy.

    --
    Vic Roberts
    http://www.RobertsResearchInc.com
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.

    This information is provided for educational purposes only.
    It may not be used in any publication or posted on any Web
    site without written permission.
     
  20. Guest

    |>No doubt. Maybe one day the lighting industry will figure out how to
    |>properly smooth out the DC?
    |
    | They already know, but it costs more money than most
    | consumers want to pay.
    |
    |>Hint: it can be done without those big
    |>capacitors that power supplies of days gone by had. One idea that
    |>comes to mind is to chop the current with a pulse width varied to
    |>compensate for the lower frequency component(s) of the ripple.
    |
    | I large number of circuits that have high input power
    | factor, low energy storage requirements and low DC ripple
    | have been published and/or patented. However, all cost
    | money and all dissipate energy.

    So just how much are we talking about to make a CFL that does not flicker?
    I'm looking for two pricings. One considering that non-flicker CFLs might
    be made mandatory and therefore would be forced to have economoy of scale
    and thus a lower price, and one considering that flicker CFLs remain the
    popular item and non-flicker CFLs remain high at least in part due to the
    lack of economoy of scale. I want to use these figures during the coming
    election to argue that our Congresspeople should dump the law they just
    put in and start over with a better one (but I don't know just yet what
    that should be). My dissatisfaction over the current one is, however, a
    typical example of the junk we get from Congress. There are no standards
    for forcing the market to have decent CFL devices. Of course for myself,
    I would want not only the non-flicker devices, but also ones that have a
    reasonably continuous spectrum (merely balancing 2 or 3 color peaks to get
    an average white of the desired color temperature is not good enough).
     
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