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IAEEL Newsletter 2/97

Hannover trends in electronics for fluorescent lighting

The trend towards smaller electronic ballasts for fluorescent lamps is here to stay. Most of the new generation of electronic ballasts presented at the Hannover Fair in April 1997 have power characteristics far better than required by international standards. Although the integration with controls is slowly moving forward, digital ports for ballasts are still an exception.

Osram's range of square ballasts for CFLs

Below is a short, but far from complete, overview of the European developments in the ballasts and electronics field for fluorescent lighting. Most of these developments have been presented during the first half of 1997.

T5 ballasts are coming for the whole range of T5 lamps, but dimmable ballasts will not be widely available for all lamp wattages for at least a year. This delay is due to the fact that lamp specifications were not ready until recently. For the new high-output lamps and circular lamps, specifications are not yet finalized.

MORE VARIETY
Manufacturers are also offering more variety in their product ranges. One example is Austrian-based Tridonic which plans to launch a new series of electronic ballasts late this autumn. They will be out in two versions: A more expensive dimmable ballast named Excel, which can switch on a lamp at a one-percent dimming level (Until now, lamps could not be switched on at a lighting level below ten percent of maximum light output.).

Thus, in a daylight dimming system where lamps are switched on when daylight reaches a certain level, people are more likely to notice. When lamps are switched on at one percent, this is likely to pass unnoticed by occupants of the room. The cheaper and simpler dimmable ballast named Eco, will only dim down to 10 percent.

Tridonic will put much effort into marketing their dimmable ballasts, and the manufacturer has even developed a simple software application "Pay-back" that allows the user to calculate energy and cost savings from applying dimmable ballasts compared with a number of ballast options. Another good example of the variety offered is the increasing number of square ballasts for six- and four-finger CFLs, and 2D CFLs. Osram, for instance, offers a compact ballast for CFLs that doubles as a lamp-holder, thereby reducing the need for wiring and separate lamp-holders within the luminaire.

DIMENSIONS

  • Ballasts are getting smaller and more compact. Until today, the cross sectional dimensions of 40-42x28mm were very common for electronic ballasts. The "new standard" that seems to emerging for both 1- and 2-lamp ballasts is 30x28mm. All major (European) manufacturers are moving towards this size, for T8, T5, and two-tube CFL 36/40/55W-lamps. Ballasts are also getting shorter. Osram, for instance, presented a ballast that is about a third the length of previous standard electronic ballasts.

  • USA-based ESI (Energy Savings) has presented a very small or "low" version. The ESI ballast is only ~18 mm high. Magnetek is reportedly introducing something similar on the market, but the dimensions of their ballast were still not known at the time that this newsletter was printed.

    The cross section of ESI's new flat ballast (natural size)

  • Integrated circuits help to reduce size, as well as operating temperatures and production costs.


ELECTRIC FEATURES
  • Many manufacturers offer ballasts with low total harmonic distortion (THD) and an improved power factor, far better than that required by IEC and EN standards. This is important, especially in large office buildings and hospitals, where lighting can make up a significant part of the total load. Many new ballasts now are in the range below 5% THD. The important third harmonic in Osram's 2x58 W ballast, for example, is below one percent. Moreover, losses are reduced in this ballast. Previously, the total power consumption for a luminaire with 2x58W lamps, including the ballast, was about 114W. Now, it is down to 110W.

  • Virtually all ballast manufacturers now meet European Union Electromagnetic Compliance (EMC) standards.

  • Some manufacturers have combined emergency-units and electronic ballasts, thereby reducing costs and space-requirements (e.g. Bag-Turgi and Magnetek).

  • Most manufacturers are introducing some sort of power control that keeps the input voltage to the lamp constant regardless of variations in supply voltage. This helps lamps last longer and reduces the risk of early lamp failure. Philips claims to be the first manufacturer that has totally independent cathode-heat and lamp current control thanks to their "alfa-control" system. According to Philips, this is most important in dimming at levels below 10 percent for some new lamp types, including T5-lamps; lack of independent control is claimed to cause severe lamp-end blackening and reduction of lamp life below these dimming levels.


CONTROLS
  • Most ballast manufacturers have presented a simple photosensor that can be connected directly to the ballast without a special interface. The photosensor must be individually set for each luminaire. The common practice has been for ballast manufacturers to offer an interface to their ballast that can be connected to any of the common bus systems, i.e. the Echelon, European Bus, or 1-10V analog system.

  • Although a standardized digital port in dimmable ballasts is in the pipeline, it will likely take years for it to become widely adopted by the industry. (Today the analog 1-10V dimming port is the industry standard). Presently, only Tridonic has said they will have such a port in their new range of ballasts, to be launched late this autumn. Many manufacturers believe that digital dimming will be widely available in a few years' time. Still, others believe that analog systems, which are still simpler and cheaper, will continue to dominate the market for many years.

  • Many luminaire manufacturers offer - correspondingly - luminaires with daylight dimming. In 1993-94 UK-based Thorn and Belgian ETAP were two companies that presented a system with dimming functions integrated in the luminaire, but ETAP also had a luminaire with occupancy control for the task component as well. In 1996-97, others introduced this feature, including the Swiss manufacturer Regent which has an up-market free-standing luminaire for office lighting purposes.

    Schematic illustration of Regent's new free-standing luminaire with integrated dimming and occupancy control

  • Helvar, Tridonic, and others have their own simple control systems for larger installations. These can be integrated with Echelon or with the European bus systems, but also work in circuits with bus systems exclusive for the various manufacturers. GE and Lutron also offer smaller control systems.


Nils Borg