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FEL and FLK

Discussion in 'Lighting and Electrics' started by propmonkey, Dec 24, 2004.

  1. JD

    JD Well-Known Member

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    Shelf life... Interesting. I have a number of lamps left over from my days in the 1980s so they are over 35 years old. Mainly PARS, NSP, VNSP. They all seem to work fine. Even have an old box of FEL lamps. They work too.
     
  2. ship

    ship Senior Team Emeritus Premium Member

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    19.5+ years where I work and many lamps long pre-dating me. Have to inventory every year lamps. But more, I have heard or toyed with this filament sag idea or problem. One would think it possible or feasible a shelf life for filament lamps.
     
    RonHebbard likes this.
  3. DELO72

    DELO72 Well-Known Member

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    Shelf life of a lamp is typically based around the condition of the potting cement. Once the potting cement crumbles and dries out (8-15 years depending on humidity, environment of the storage area?), then the lamp capsule isn't supported well in the base and shouldn't be used. But the inside burner/capsule components typically don't go bad over time from lack of use, so really it's just the potting cement that "goes bad" in my experience.
     
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  4. DELO72

    DELO72 Well-Known Member

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    I disagree on the GLA > GLC. If you buy a GLA you get a long life, dim lamp. If you buy a GLC you get a High Output, normal life lamp. AND-- if you run that GLC at ~90% intensity, you get a GLA. I'd rather have TWO options out of one lamp than only one option. :)
     
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  5. ship

    ship Senior Team Emeritus Premium Member

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    Thanks for your above info on shelf life!!! Very important to keep in mind as a base for info.

    As for GLA/GLC, I go to the concept of it's about the luminous output of the stage for the fixtures. If over the past say 100 years, art was made with what ever lumens were put on stage with electric lamps, once the house lights go down and the stage lights gently come up to a scene.... the eye balls will adjust to what lumen levels are provided after the blackout. Eyes are getting adjusted to lower luminous levels and you now have a lot of head room in providing specials or scenes, but long life as a goal for the norm.
     
  6. FMEng

    FMEng Well-Known Member Fight Leukemia

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    I don't care for the yellow shift of long life lamps. Plus, there are those times when, to borrow an audio term, I need the full dynamic range from the full output of a standard lamp. For everyday use, I run at less than full level which extends the life considerably. The best of both worlds.

    For example, I just lit a voice recital tonight with a pale skinned red head. I gelled the lights with more dense gels than usual, and appreciated having the 1000 Watt, FEL lamps to compete with the evening sun coming in through the windows. Any other lamp wouldn't have cut it due to those factors plus the long throw.
     
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  7. techieman33

    techieman33 Well-Known Member

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    Your not always lighting for the human eye though. Sometimes you have to light for a camera too. And when your doing that the lumens matter.
     
  8. ship

    ship Senior Team Emeritus Premium Member

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    For instance to use high output or 1Kw, where I work, we certainly are high output unless for a store X-Mass install say. If you have the budget - sure why not. FEL I would say A GLD at 115v should be tried given its higher color temperature. Camera too. For a normal theater use.... I stand by the concept of go long life lamp.l
     
  9. DELO72

    DELO72 Well-Known Member

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    Err.. I just realized what a terrible sales person I am! What I MEANT to say is that lamps...err..absolutely "go bad" after... umm... let's say a year, and you should definitely throw out all "old" lamps and buy new ones that are fresher! :) As John Lovitz used to say, "Err.. yeah-- that's the ticket!"
     
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  10. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @DELO72 To maximize shelf life, is it better to store lamps in the dark or in sunlight? Is the loss of lumens and lux increased when darkness prevails and sucks the light out or is it better to bombard idle lamps with sunlight? Is this anything to do with some manufacturers shipping lamps in white Vs. colored packages??
    Toodleoo!
    Ron Hebbard
     
  11. DELO72

    DELO72 Well-Known Member

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    I think it is best if you take the lamp out of the box once per day, show it the sun (Perhaps by placing it just for a moment in direct sunlight), and speak words of inspiration to it, such as, "Hey little fella- you could one day be this bright too! You just have to TRY." Use positive reinforcement and supporting comments in a soothing voice, to try and inspire the lamp to be the best it can be, while gently stroking the side of the lamp base (with a clean cloth). I don't have an conclusive data showing that this actually helps, but I can't see how it can hurt.
     
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  12. ship

    ship Senior Team Emeritus Premium Member

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    So the concept is filament sag due to gravity. Tungsten filaments are appairently very hard structures inside a lamp, but gravity should have effects on such a filament both in stretching and sagging. This should take a few years to have sufficient effect but will eventually. Notes of spinning follow spot lamps not persay associated with this, in use not really a concept of storage of elder them or filament lamps. Probably depends on years and not so much say turning the lamp in storage every year (might help), but overall there is a defined usable gravity effect on a lamp filament or even electrode I would think. Thanks Mark for providing some semblance of a storage concept not otherwise studied or asked about.
     

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