Osram joins induction family
Several years after Philips and GE introduced an electrodeless, fluorescent induction lamp, Osram is launching one of its own. The company has chosen to call its 150-W, 12 000 lumen-system "Endura". The rated life of Endura is 60 000 hours, which is the same as that of Philips' QL system, launched in 1991. It should be noted, however, that Philips, GE and Osram offer three very different induction lamps, each intended for a different niche. 
Whereas GE's 23-W induction lamp has a standard E27 (Edison) socket, a rated life of 15 000 hours, and is intended as a retrofit lamp for applications where the 100-W incandescent standard reflector lamp is presently used, i.e., downlights and spotlights, Osram's Endura and Philips QL lamp system requires a special external ballast and luminaires designed exclusively for the respective light source. The lumen packages offered by Philips' and Osram's systems are much higher than that offered by the GE lamp but there is a great difference between the Endura and the QL system: The QL lamp systems, with their 55-W/3500-lm and 85-W/6 000-lm packages, seem to be aimed at outdoor park luminaires and indoor public and architectural lighting. The Endura system, however, with its 150-W/12 000-lumen package, is presented by Osram primarily as a lamp for tunnel lighting and for industrial applications where maintenance is costly or difficult.
LESS DIFFERENCES
Both Osram and Philips seem to be moving towards each other, however. Philips is planning a 12 000-lm package for 1998, whereas Osram is planning a 100-W/8 000-lumen package.
With its 150 W and 12 000 lm Osram claims that the Endura system is the most efficient electrodeless fluorescent lamp ever made. (Note that Fusion Lighting's electrodeless sulfur lamp is not a fluorescent lamp, nor does it use induction to generate light, see IAEEL Newsletter 3/94). Although Osram's claim seems to be true, the higher system efficacy (80 lm/W) compared, for instance, with Philips QL lamps (63 lm/W for the 55-W and 70 lm/W for the 85-W version), can be explained by the high lumen package of the Endura lamp (There is a sort of economy of scale that typically applies to light sources: Higher power generally means more lumens per watt for any given technology). However, there is a problem with extremely powerful lumen packages - if they are not applied carefully, it may be hard to utilize all the light efficiently. This means that under certain conditions, an installation with powerful, highly efficient light sources could actually be less efficient than an installation with light sources with less power and efficiency but with a more appropriate sizing (in terms of, for instance, W/100lux/m_2).
DIFFERENT LOOK
The New Endura lamp has a unique look.The best description is a rectangle with a metal ring around each of the short sides of lamp. The metal rings serve as antennas.
At 250 kHz, the Endura lamp runs at a frequency 4-6 times that of most electronic ballasts for fluorescent lamps, but at a much lower frequency compared with both the GE and Philips systems, which are operated in the MHz and GHz range.
The price of the Endura lamp should be between DEM300 and 350 (USD 190-210) including the control gear. This is roughly equivalent to that of the QL system, although one probably gets more lumens per unit cost out of the Endura system. To fairly compare these light sources in terms of economy, however, one would have to consider the whole installation.
Nils Borg