Light levels

Discussion in 'General Electronics Chat' started by inwo, Sep 6, 2014.

  1. inwo

    Thread Starter Well-Known Member

    Nov 7, 2013
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    Rather than hijacking a thread where #12 posted about rpm cube rule.............

    Does anyone know how much to increase lumen output to double light level?

    4 times? Square rule. Cube?

    Ignore the details if possible. Just ball park.

    Over head light (high bay) outputs 120 degree pattern.

    For example. If I have a 5,000 lm source now and want to double the light level in the area covered by the 120 degree pattern.

    More questions to follow if there's an expert here.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,553
    2,375
    Not answering your question, but one thing I found was that also light technology is important, depending on what the facility does, locally a recent change by a bus manufacturer to increase the lighting in their wire stripping and harness facility, resulted in perceived colour change in some wire colour's to an entirely mis-read of the true colour.
    Max.
     
  3. inwo

    Thread Starter Well-Known Member

    Nov 7, 2013
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    Haven't found much yet.

    Near as I can tell it's 1 to 1. lamp lumen to lux at a given distance.

    Inverse square with distance.

    So if I double lumens I double lux at the same point.

    If true it will make life easier. :)
     
  4. #12

    Expert

    Nov 30, 2010
    16,304
    6,814
    I think you're right on both constants.
    Where did I learn this stuff?
    GE lighting catalog? No.
    Physics 101? No
    Ack! Senior moment!

    Probably, "Google is your friend" in this case. Start with the definition of a Lumen or a foot candle and you will probably find the answers.
     
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  5. bertus

    Administrator

    Apr 5, 2008
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  6. wayneh

    Expert

    Sep 9, 2010
    12,137
    3,054
    Sounds good to me. Lumens is total output, lux is just lumens per area, and area increases with the square of distance. Once distance is fixed, double lumens gives double lux.
     
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  7. NorthGuy

    Active Member

    Jun 28, 2014
    604
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    And if you build a reflector, you'll also add the light that would otherwise go to the other side.
     
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  8. inwo

    Thread Starter Well-Known Member

    Nov 7, 2013
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    Sounds promising.

    If I use a 120 degree led down-light @ twice the lumens, I could get 6 times the light level. Maybe 4 or five considering reflected light from the original 360 degree bulb.

    Calculator: http://www.kurtzon.com/Calculator

    Don't know if the CU can be over 1 if all light is concentrated.

    Edit
    calc. lets me input a 2 or three with expected results. Don't know if it's valid. ??
     
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