Compact fluorescents

Discussion in 'General Electronics Chat' started by PackratKing, Aug 20, 2011.

  1. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    How many on here have had an experience with compact florescent bulbs, specifically the two-prong mount as opposed to screw in........spontaneously exploding.

    I just had one blow the cover off an unventilated ceiling fixture in my grandsons' room........scared the bejesus out of him. It left a 3" dia. flash burn on the cover, and has a very swollen electrolytic capacitor on the PCB, and a lot of charring.........autopsy not complete...pictures to follow if wanted

    My first thought [ maybe shame on me ] was about the cheap Chinese manufacture of the bulb. Second, the unventilated nature of the beast -- also chinese........... could simple overheating have done the deed??

    I don't think I will leave the fixture in service, 'till I can find a decent American made replacement.
     
  2. debe

    Well-Known Member

    Sep 21, 2010
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    If the heat cant get away from them the base will over heat, usual failure is the electrolytic just after the mains rectifier. Havent had one explode yet but seen plenty that the capacitor has dried out & lamp wont work.
     
  3. Audioguru

    New Member

    Dec 20, 2007
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    American companies buy very cheap compact fluorescent bulbs from China then resell them and make a huge profit.
     
  4. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    Debe.......that's the problem........you just confirmed what I thought.....the mains rectifier went first, one leg vaporized right off the PCB, and likely responsible for most of the flashmark on the cover. The capacitor is badly swollen, but did not pop.

    I think I will be paying a visit to the Orange or Blue very soon. I'm willing to bet that only a small fraction of these incidents get reported.........
     
    Last edited: Aug 21, 2011
  5. debe

    Well-Known Member

    Sep 21, 2010
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    This is a cheepo Chinese CFL new. I usualy get 3-4yrs out of them & have replaced the 400V cap in them to get a bit more. Hardly worth it at $4 each! The little yellow sleeved object is a fuse, that should have blown.
     
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  6. Hi-Z

    Member

    Jul 31, 2011
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    You have to be careful with those fluorescent bulbs - they contain a small amount of mercury, so it's not good news when they explode. If this happens, get out of the room and open the windows. Also, be careful how you dispose of the damn' things.
     
  7. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    :DThanks for responses all !!

    Audioguru -- unfortunately you are right on the china issue, which is a major boiling point for me, and I'm quite sure many others.

    Debe, I will check the fuse to see if it did its duty.....also, did you note if the input wiring - four "posts" - on any you've seen, were connected w/ wire-wrap, and decidedly corroded ? do you think that fact could contribute to the rectifier erupting ?? or note that the solder appeared inadequate ??

    Hi-Z -- The tube where the mercury lives did not rupture, I will definitely dispose of same after I chew on blue or orange about it, and ask our local fire company how common this is........

    Edit: there is no fuse evident on the remains of the PCB.
    And if you ask me, Mr. overkill, :p the rectifier diode awa other components, are too freekin' tiny !
     
    Last edited: Aug 21, 2011
  8. Audioguru

    New Member

    Dec 20, 2007
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    My electrical distribution utility company gave away Chinese compact fluorescent bulbs for free. I took many.
    Then the bulbs were recalled because the Chinese manufacturer cheated and used the certification number of another company so their bulbs were not certified to be safe. Some dripped flaming plastic when they failed.
    They were all replaced.

    I agree that most of my "certified" compact fluorescent bulb failed after a few years because their electrolytic capacitor swelled and/or shorted due to the too high temperature.

    When a bulb fails then I simply phone the American importer (no charge long distance but their American Southern accents are difficult to understand) who sends me a coupon to buy more for free.

    ALL my existing compact fluorescent bulbs are free replacements.
    Over and over and over and over and ....
     
  9. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Are you saying no Canadian company does this? If this is so, how do they get around not doing it?
     
  10. tom66

    Senior Member

    May 9, 2009
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    I somehow doubt the claimed 15,000 hour lifespan.

    I have seen newer CFLs using a 2.8µF cap instead of a 3.3µF one after the mains rectifier. The slightly reduced capacitance will probably work okay for a few years but the aging of the capacitor will kill the lamp after time. On start-up, if the ripple is too high, the Royer circuit will probably fail to oscillate, or when running, the bulb will have 100/120 Hz flicker.

    The lamp itself might last 15,000 hours but the built in ballast won't. One of ours is less than 2 years old and is making a buzzing sound already, which is worrying.

    About a year ago many retailers in the UK were practically giving the bulbs away. You could buy 10 for £1 at one retailer; we have 50 stocked up somewhere in this house.
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    Most "Canadian" electrical companies are actually just the foreign office of an American or European one. They don't make anything. Instead they just buy cheap Chinese stuff and sell it at a huge profit. I use Osram-Sylvania compact fluorescent light bulbs (Osram is European and Sylvania used to be an American company) because I like their 3000 degrees pure white colour. But they don't sell 3000 degrees pure white anymore, just 2700 degrees "warm white" (orange) or 3500 degrees "daylight" (blue) ones.
    They last for a few years then I phone them and get a coupon for free replacements. Over and over and .....
     
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