Re: GLA filament failure


I have mixed feelings about the fixture. It does have a glass reflector,
and doesn't eat gobos. They don't seem as well built as an S4 but
they are usable at least now while they are still pretty new.
I had originally thought that the filament was only supported at the ends,
but in fact there is a center support. The failed lamps have small black
spots
presumably where the filament failed initially. The filaments are in pieces

I looked at the lamp in the reflector and it is pretty well centered on the
one
that is in there now. I might have not seated the others that failed
quite the same way though. I've never really given orientation much thought
since the fixtures switched over to axial lamping.

I'm pretty much the only one that has touched anything since the room was
opened in the Fall of 2007. The only thing that changed was me changing
the lamp in that fixture and having it fail as soon as I moved the light
to focus it. Even when I was being unduly gentle.

I'm just trying to establish whether there are specific lamps I should avoid
from
specific manufactures. Unfortunately I forgot to get the name of the
manufacturer
until I went in today.

Thanks for your concern.

David

David,
That there are black spots, on the envelope I presume, and the
filaments are in pieces again tells me there is either a voltage
problem OR loss of gas. If the lamps have cracks in the base (going
back to my scenario where you got the new guy), or miniscule fractures
in the envelope, then they're going to blow. Please check the
voltage! Did your local utility do any recent work on your
transformer or feed?

LJ
.

Relevant Pages

  • Re: A Narrative History of the Light Bulb
    ... These energy saving lamps were made by US firm Duro-Test. ... coating, secondly the spherical glass bulb, or rather a method of accurately ... mounting the filament directly at the centre of the bulb, ... It demonstrated real energy savings of about 30%. ...
    (sci.engr.lighting)
  • Re: How do Philips X-treme power bulbs work?
    ... What happens is the broken ends of the filament ... swing around and if they happen to touch, the arc which is generated ... I've done such a repair on ... many lamps could easily be in the hundreds or even thousands of volts. ...
    (sci.engr.lighting)
  • Re: The Rebirth of the Incandescent Lamp
    ... It will be interesting to see if lamps can be made that meet ... Philips Halogena Energy Saver is already available ... that the efficacy goals were set so low. ... filament tubes we have had for decades in reflector lamps, ...
    (sci.engr.lighting)
  • Re: Lumen Output of Incandescent Bulbs
    ... percent more light output from the 150 watt bulb when running at full ... three lamps. ... The filament of the 150 watt bulb is further away from its base, ... lower voltage incandescent lamps be more efficient than higher voltage ...
    (sci.electronics.design)
  • Re: Lumen Output of Incandescent Bulbs
    ... That's 20 percent more light output from the 150 watt bulb when running at full voltage. ... and put a 150 watt bulb in one of a pair of lamps and compared it's brightness to the two 75 watt bulbs in the other lamp. ... The filament of the 150 watt bulb is further away from its base, so there's a longer thermal path along the filament supports to suck heat away from the filament, and because it's further away from the filament, the base obscures and absorbs a smaller percentage of the radiated visible light. ... When lamp wattage increases and lamp cost increases less, the percentage of bottom line cost being from power consumption increases and the percentage of bottom line cost being from lamp cost decreases. ...
    (sci.electronics.design)
Loading