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Lightbulb burnout

  1. Jan 14, 2016 #1
    So I purchsaed this 6300 lumen light bulb, clear white glass, with a tugsten fillament.

    I have this small desk lamp that used to have some 30 or 60 watt light bulb installed. I replaced that with the more powerful one, but.... why did the more powerful one burn out? One day, it just burned out. And I only had it for a few hours. Is it normal for a bulb to be..... really really hot? I felt like you could heat a small room with the bulb alone.

    Is there something with the voltages or current?

    I mean it's a normal 120 volts, directly into the wall socket.


    I don't get this. SHouldn't any bulb work? No matter the lumens? (I know luminosity isn't the proper measurement, but there's basically a correlation. Right?
     
  2. jcsd
  3. Jan 14, 2016 #2
    Lamps usually have a sticker saying the maximum allowed wattage. If you use bulbs with more power, you risk fire etc.

    I guess that you used a halogen light bulb. Those need to be handled with care, the glass surface must not have fingerprints.
     
    Last edited: Jan 14, 2016
  4. Jan 14, 2016 #3

    CWatters

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    How well ventilated is the light fitting? A more powerful bulb may run hotter.
     
  5. Jan 14, 2016 #4
    It's about as well ventilated as possible, it's completely open except for an open cyllindrical lampshade around it.

    What do you mean by allowed wattage in lamps?
     
  6. Jan 14, 2016 #5
  7. Jan 14, 2016 #6

    Drakkith

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    Lamps can only handle so much power running through them. If you put in a bulb that exceeds the allowed wattage you risk burning out the lamp's wiring, starting a fire, etc.
     
  8. Jan 14, 2016 #7
    Wait..... so how do bulbs more than 60 watts ever plug in anywhere? I've never seen anything like a 100w socket or whatever.
     
  9. Jan 14, 2016 #8
    For small desk lamps—which is what you mentioned in your original post—60 W is a typical maximum rating. The table lamp I have in my living room is rated at 150 W. It just depends on the lamp.
     
  10. Jan 14, 2016 #9

    DaveC426913

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    Sure, most desk lamps are rated at less than other receptacles, but that's to protect the lamp from melting not to protect the bulb from burning out.

    Any reason not to assume the OP just got a bad bulb? Or is it possible that a higher wattage bulb gets more brittle?
     
  11. Jan 14, 2016 #10

    davenn

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    This is the most appropriate and most likely reason


    Dave
     
  12. Jan 14, 2016 #11
    True but over-heating is a common cause for short bulb life.
     
  13. Jan 14, 2016 #12

    DaveC426913

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    The OP said 6300 tungsten bulb. Halogen bulbs are often not compatible with different wattages of other halogen bulbs, let alone with tungstens.
     
  14. Jan 14, 2016 #13

    davenn

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    Any of the high wattage bulbs are susceptible to fingerprints on the glass envelope
    still a very valid answer :smile:
     
  15. Jan 14, 2016 #14

    DaveC426913

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    Yeah but that still doesn't make sense. Why would a bulb in an open lamp (as the OP points out, as open as it can get) overheat more than the bulb stuck in some enclosed lamp supporting a higher wattage?
     
  16. Jan 14, 2016 #15

    DaveC426913

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    I know halogens are. I am highly dubious that tungsten bulbs are. I don;t think the OP is talking about anything more powerful that a 100 or 150 watt bulb.

    Well, OK. Here's a 300W 6300 lumen tungsten:
    https://www.fastenal.com/products/details/0710993

    Though I'm not sure these giant mostly-vacuum bulbs are susceptible to fingerprints like tiny halogen.
    0710993.jpg
     
  17. Jan 14, 2016 #16

    davenn

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    I have seen more than a few tungsten floodlight lamps die for that reason ... hell probably killed a couple myself before anyone told me DONT TOUCH the glass ..... hahaha
    It's the fingerprints that cause hotspots on the high temp glass


    don't forget they are all tungstens ... halogen is just the gas filling :wink:
     
  18. Jan 14, 2016 #17

    DaveC426913

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    OK, I see your point.

    Maybe we should stop guessing and ask the OP exactly what bulb.
     
  19. Jan 14, 2016 #18
    Halogen bulbs have tungsten filaments.
    Anyway, the OP did not provide that much information about the bulb or about the point of failure, so we are just guessing.
     
  20. Jan 14, 2016 #19
    There isn't a direct correlation between power consumption in watts and amount of light produced measured in lumens.
    However the old style incandescent bulbs are one of the most inefficient ways of doing it, halogen bulbs are only slightly better.
    You could get around 3x better efficiency with flourescent and up to 6x with LED units.

    Describing the heat produced by this 6300 lumen rated incandescent bulb as 'enough to heat a small room' is probably close to the truth.
    A bit of googling revealed that a standard 100W incandescent bulb produces around 1600 lumens.
    Your bulb which broke is equivalent to four of those, so power consumption should be in the region of 400W - which is indeed about right for a small electric bar/coil heater.
    I don't know in what situation the unit was intended originally to be used, but my guess is that forced ventilation might have been necessary.
     
    Last edited: Jan 14, 2016
  21. Jan 14, 2016 #20
    Oh no no no it was about 300 watts, (so yes close to what rootone said) standard filament, 6300 lumens. If you put paper on it, I would expect, or at least it felt like the paper would probably ignite after a while. Or at least burn up very slowly from the intense heat.

    But anyways thanks everyone. I think that's about it for my questions.
     
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