Arc Prevention in Tungsten Halogen Studio Lamp Applications
Almost all production personnel in the film and television industry have at some time encountered sudden failure of incandescent studio lamps. When this occurs at a crucial moment and forces a
The significant features of these failures were that they almost always occurred during the first 20 hours of use and the incidence of failure increased with operating temperatures. Failure invariably resulted from an arc across the filament plugs which destroyed the tails of the filament.
Tungsten halogen lamps are gas filled. The introduction of hydrogen is predicted to react with the halogen to ‘slow down’ the tungsten halogen cycle. In addition it is known that hydrogen will slowly diffuse through the hot quartz bulb so that the hydrogen concentration would gradually diminish.
The rate of loss of hydrogen during lamp operation is less than previously predicted and based upon spectraradiometer measurements and calculations, maximum protection is only required during the initial 50 hours of life. Hence the use of hydrogen additions is the most advantageous method of ensuring reliable operation of lamps during early life, particularly in demanding operating conditions.
GE Lighting offer lamps with proprietary hydrogen addition*.This offers adequate arcing protection without significantly interfering with the halogen cycle.
*owned by GE under US PAT #4743802
