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Compact Fluorescent Lamps...

Discussion in 'Electronic Design' started by Chuck Harris, Feb 24, 2006.

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  1. Chuck Harris

    Chuck Harris Guest

    Am I the first to notice that CFL's really beat the poogies out
    of their light switches?

    Charging the 10uf cap in the CFL's switching power supply really
    makes a nice "pop" in the wall switch on turn on... particularly if
    you have more than one CFL in the circuit. I wonder what
    affect of the surge is on the overall lifetime of the switch?

  2. DJ Delorie

    DJ Delorie Guest

    I have 12 CFLs in my basement on one switch, and haven't noticed any
    popping sound.
  3. Phil Allison

    Phil Allison Guest

    "Chuck Harris"

    ** I just bench tested a Philips brand CFL rated at 11 watts and 220-240
    volts with the following results.

    Current draw = 80 mA rms.

    VA = 19.2.

    I pk (repetitive ) = +/- 250 mA.

    I transient max = +/- 17 amps.

    Chuck has a case.

    ......... Phil
  4. Oppie

    Oppie Guest

    Isn't an inrush limiter like a PTC thermistor used?
  5. WHAT! adding USD 0.0000001 a piece to the manufacturing costs. ARE YOU

    No. ;-)
  6. Chuck Harris

    Chuck Harris Guest

    No. CFL's are super simple HF inverters. They are
    powered by a bridge rectifier with a capacitor input
    filter. They use a pair of FET's as the active elements,
    and a tiny little toroid transformer.

  7. Chuck Harris

    Chuck Harris Guest

    I am using mostly Consumer Electronics, and FEIT CFL's. And because
    I use them base up, they fail fairly quickly from the generated heat.

    The Arcing doesn't happen all of the time, but mostly on circuits where
    the CFL's are fairly old (over 1 year). Since the lamps always fail with the
    10uf electrolytic going open, I am wondering if the sparking is due to
    an excessive amount of HF showing up on the line. It is probably time
    for me to put some instruments on the line and see what is really going

  8. Poogies? Such language!

    I guess it depends on the lamp. Some have a short turn-on delay, which
    I've always assumed is due to some sort of surge controlling
    thermistor. The 1-second delay is a bit annoying, but could help
    extend the life of your light switch. Then again the switch on our
    garbage disposer is 20+ years old, emits a loud *poogeie* every time
    you turn it on or off, and is still working fine, so I wouldnt worry
    too much about your light switch.
  9. Glen Walpert

    Glen Walpert Guest

    This is only an issue with the crap low end switches almost
    universally installed by builders here. The local supply store will
    have these in a bin for .19 each, as well as "spec" or commercial
    grade switches for 1.29 each or so. Be a big spender, upgrade your
    switch and the problem will go away.
  10. Ian Field

    Ian Field Guest

    Some years ago I added inrush thermistors to most of my lightswitch plates
    to prolong the life of the filament bulbs. As soon as the local store
    dropped the price of CFLs to £6.50p I replaced all the filament bulbs. At
    this stage I used to repair any that failed, and at the same time fit an
    inrush thermistor in the unit. Then the store dropped the price of CFLs to
    £1.99p so now I just throw any that fail and buy a new one!

    Most of the light switches still have thermistors - this seems to prolong
    the life of both the switch and the reservoir electrolytic in the CFL - I've
    never done any measurements to confirm it, but I've always suspected that
    the inrush surge is greater on a filament bulb. Try measuring the cold
    resistance of a filament bulb with a DMM and calculate the current and
    compare that to the operating current calculated from volts & watts.
  11. Warren Weber

    Warren Weber Guest

    I have noticed that on one switch (builder put in) have 4 lamps (400 watt
    OUTPUT) don't recall input wattage. WW
  12. Chuck Harris

    Chuck Harris Guest

    Oh, you mean like the "crap" Pass & Seymour legrand commercial
    grade "spec" switches that I used when I wired my house?
    (yes, I wired the whole house.)

    I learned long ago that labor figures so heavily in electrical
    wiring, that trading quality for a small savings in parts cost
    is a bad deal.

    It isn't the switch, it is something to do with the

  13. Spokesman

    Spokesman Guest

    In the plant I where I manage the elctrical department we are
    almost eclusively going to CFL. We have many areas completely
    changed and some have been operating for over 6 years now
    with no apparent degradation of any switches. Many of these CFLs
    are 26 watt units replacing 150 watt incandescent in Cl II Div II areas.
    The energy savings is significant after you convert a few hundred fixtures
    to CFL.
  14. Oppie

    Oppie Guest

    Significant energy savings over incandescent and better power factor vs
    'core and cap' fluorescent ballasts are why the utility companies often give
    rebates for updating your lamps to CFL or electronic ballasts.
  15. Phil Allison

    Phil Allison Guest


    ** Not true.

    The PF of CFLs is *very* poor, due to the spiky current waveform.

    A standard fluoro with cap draws a near sine wave current and is close to
    being in phase.

    " I just bench tested a Philips brand CFL rated at 11 watts and 220-240
    volts with the following results.
    Current draw = 80 mA rms.
    VA = 19.2.
    I pk (repetitive ) = +/- 250 mA.
    I transient max = +/- 17 amps. "

    ........ Phil
  16. Oppie

    Oppie Guest

    I can't refute that but I did look further into energy supplier rebate
    programs here in NY/USA. I had originally thought that the driving force was
    to push for higher power factors so that the utility would have reduced
    current demand (for an equivalent watts). Now it seems that they are simply
    pushing for more efficient lighting - CFLs being a prime example.

  17. Joel Kolstad

    Joel Kolstad Guest

    This is an overgeneralization. Not quite a couple years ago I had reason to
    sit down and measure the input current voltage waveforms of various CFLs, and
    there was a mix of those with "spiky" current inputs as well as some with very
    clean, high power factors. I believe the later were new GE bulbs.

    Power factor information certainly doesn't routinely make it onto the
    packaging, though.
  18. repatch

    repatch Guest

    Very true. In the beginning CFLs were generally quite horrible with power
    factor and "spikey" waveforms.

    These days some CFLs are actually pretty good. Europe I believe is the
    area that is trying to push ALL devices using switchers to be more
    "friendly" to the power grid, mostly for EFI reasons I believe.

    That said, I still can't find a CFL at the local home improvement store
    that has a power factor of better then say 0.6. And you have to really
    look to find the info needed to calculate the power factor, nevermind the
    power factor actually being ON the box (because that would of course
    confuse consumers, less info=better for companies...).

  19. Joel Kolstad

    Joel Kolstad Guest

    ComCast, the local cable TV and an Internet service provider, recently had a
    campaign touting their move to faster cable modem connection speeds, "3 megs!"
    What they meant was "3 megabits per second," but I'd be amazed if the average
    consumer had a clue how many "megs" they had before and hence why "3 megs!"
    was better... Just wait, in a few months they'll be advertising "6 megs!,"
    just by redefining "meg" as "mega-half-bit per second..."

    I also find it highly annoying how nearly all laptops today are advertised
    only as "17" LCD!" and nowhere is the actual resolution given. Even Dell only
    lists something like "SXGA+ 17" LCD!" and you then have to dig around to find
    how _they_ define "SXGA+" vs. anyone else.
  20. I've always had absolutely abysmal luck with screw-in fluorescent lamps.

    The ordinary "quick-start" 8' fluorescent tubes in my office, however,
    have been on 24/7 for almost three years, except for when they plug in
    too many grinders simultaneously on my office circuit. ;-)

    (they don't like doing this, because the server goes down, which
    displeases the PHB. ;-P )

    Version: 3.1
    GAT(E P) dpu s: a++ [email protected] P+ L++>+ !E W+ N++ o? K? w-- !O !M !V PS+++
    PE Y+ PGP- t 5+++)-; X- R- tv+ b+ DI++++>+ D-? G e+$ h+ r-- z+
    ------END GEEK CODE BLOCK------
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