By: Craig DiLouie
Induction lamps operate without electrodes, eliminating wiring connections between the lamp and its generator or driver. Most wear and tear on the system occurs at this point, so its absence significantly extends lamp life. (Currently, there are two types of electrode less lighting; plasma lighting is the other and was the subject of this column on page 84 of the July issue.) Induction lighting consists of a fluorescent lamp with electromagnets wrapped around a section of the tube. High-frequency energy emitted by an electronic ballast (generator) is guided into an electromagnetic field around the lamp, which excites the mercury atoms provided by an amalgam pellet and produces light. The phosphor coating on the bulb wall converts this light energy into visible light through the typical process of fluorescence. The light output exits the lamp from the surface of the bulb.
“Induction is fluorescent technology,” said Jodi Vallante, product manager, Icetron Systems, for OSRAM Sylvania (sylvania.com). “However, it does not utilize a cathode or coil, which is the principal failure mode in a fluorescent lamp. This helps allow for very long operating life.”
The result is a solution that offers several significant advantages. First is longer life and associated maintenance benefits due to the absence of electrodes. Induction lamps are rated at 100,000 hours. Service life for typical fluorescent lamps is based on mortality, the point at which 50% of a large population of lamps will be expected to fail based on the operating cycle expressed in hours/start. Though the light source produces light through fluorescence, induction is rated similarly to LED and based on average lumen depreciation. For example, if the lamp is rated at 100,000 hours at L75, that is the point prior to which one-half of a sampling of induction lamps will be producing 75% of their original full light output. As with LED, it’s up to the owner to decide when the induction system should actually be replaced based on his or her light level needs.
Additionally, the system offers up to 65% lower energy consumption than HID, high color rendering, a range of color temperatures, higher lumen maintenance, and virtually instant starting and restrike capability. Induction systems are available ranging from 35W to 400W and producing 2,450 to 36,000 lumens, with a CRI of 80+ and 2200K to 6500K color temperatures.
The lamps are available in circular, linear, and bulb shapes of various sizes to satisfy different application needs, with some circular and bulb-shaped lamps available with a mogul or medium screw-in base. Cold-start and remote mounting options are also available. The solution may be purchased as a system for retrofit of existing luminaires or as complete luminaires ready for installation. (More utilities now recognize induction lighting in their commercial lighting incentive programs.)
According to Leendert Jan Enthoven, president of Briteswitch (briteswitch.com), rebates for induction high-bay luminaires range widely, but averaged $84.50 in early 2014.
Induction lighting is typically controlled in exterior applications with photocells for dusk-to-dawn operation However, some systems can be dimmed using step dimming or 0V to 10V continuous dimming from 100% to 40% of lamp power, allowing induction systems to be specified in projects complying with commercial building energy codes requiring bilevel control. Add-on com ponents can be used to achieve wireless lighting control. When dimmed, induction lamps do not have the same color shift issues as HID and plasma lamps.
“Induction is always an attractive option relative to HID, even in the medium term for new construction, given both its swift payback from energy savings and the maintenance savings available from its 100,000-hour-long life,” said Jay Matsueda, director of marketing for Fulham (fulham.com). “For existing buildings, induction is relatively easy to use for retro fitting as well, thus preserving one’s investment in existing fixtures and increasing demand.”
Induction competes with HID and also with LED, which presents another long-lasting alternative. Ironically, it appears that the proliferation of LED technology may have spurred growth in demand for induction lighting as alower-cost alternative.
“Induction saw a surge in demand in the past three years mainly in retrofit applications and especially in street and area,” said Vallante. “LED systems gave induction a surge as induction price points tend to be lower than their LED equivalents. Induction will continue to have its place in the lighting market where customers desire high-quality fluorescent performance over a very long operating cycle. The opportunities going forward will mainly be in the high-wattage, high lumen packages and 100W dimming.”
“While LED has gained a recent foot hold in down, track, sign, and display lighting applications, LED lighting remains relatively expensive compared with in duction, translating into a longer payback period,” said Matsueda. “Also, current LED technology does not yet perform well in applications with high ambient temperatures.” “Induction will always be the long-life, white light leader or alter native,” added Vallante. “Customers always like choices, and induction has proven installations of more than 10 years without having to do a chip or driver change.”
She and Matsueda caution that thermal measurements should be taken when retrofitting existing luminaires to induction. “Heat is the enemy of any lighting system, and retrofit systems sold as kits through authorized distributors have been tested to perform under specific conditions,” Matsueda explained. “One simply cannot install induction without proper thermal test ing, just as one cannot responsibly use any other type of technology without doing so either.”
The final word: “Electrical distributors can count on induction lighting because it’s a proven, reliable operation that delivers high-quality, long-life light where and when needed,” Vallante said. “For electrical contractors, this means satisfied customers.”
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