60 000 Hours of No Maintenance
60 000 Hours of No Maintenance
Philips recently introduced an induction lighting system, the QL lamp. This is the first induction lighting system on the market with a built-in antenna. The system offers almost 60 000 hours of lighting with practically no maintenance.
According to Philips, the lamp has been tested since the beginning of the 80s, and they claim the 60 000 hours can be warranted. The electronic circuitry ensures rapid lamp starting, absence of flicker and instant full light output.
The QL system has a power consumption of 85 watts with a nominal luminous flux of 5 500 lumens. This means that the lamp is reasonably energy-efficient.
The high lumen output will limit the usefulness of this light source for many interior applications. However, in the near future lower lumen packages will be introduced. In principle, dimming is possible. At the moment there is a choice of two different colour temperatures (3 000 K and 4 000 K, both with colour rendering 85). The lamp depreciates by only 10% during the lamp's life.
Induction lighting is a combination of electromagnetic induction and gas discharge lighting. An electric current passing through a coil generates a magnetic field, inducing an electric current in the gas fill of a low-pressure gas discharge lamp. A metal or ferrite core intensifies this induction. This induced current causes electrons in the gas fill to ioniase, giving rise to ultra-violet radiation which in turn is converted into visible light by fluorescent powders inside the light bulb.
The Philips system is not the only induction lighting system available on the market. The Japanese manufacturer Matsushita is reported to have an induction lighting system on the market, but the Matsushita system is a combination of lamp and luminaire with an external antenna and with less light output.
As the QL lamp works without an external antenna in the luminaire, great freedom is given to luminaire designers. On the other hand, this will mean that both lamp and luminaire will have to be exchanged after 60 000 hours.
(See also: comments and letters, and QL gets more flexible, IAEEL 1/96)
For comments see letters: An option, not a necessity (IAEEL 2/92), and Crucial maintenance (IAEEL 2/93).
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