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Taking a Look at Fluorescent Lighting Systems

Taking a look at fluorescent lighting systemsWe see fluorescent lamps everywhere. Many owners upgrade older systems to increase energy efficiency. In new construction, it’s common to specify high-efficiency fluorescents.

Some designers take this to the next level by specifying dimmers. However, installing dimmers can turn out badly if you don’t know what you’re doing.

While dimmers do extend the life of incandescent lamps, dimmers do not extend the lives of fluorescents. A mismatch of dimmer and lamp type can actually decrease lamp life.

With fluorescents, look at the dimmers, ballasts, and lamps as a system. Your electrical distributor can help you correctly match components. When discussing your project, understand that you’re working with several variables. You must control these during all dimming phases, and you can do that only by using a dimmer designed for a particular lamp.

The variables are:

  • Cathode voltage. A standard, rapid start ballast has a constant cathode voltage, but a dimming ballast should raise the cathode voltage as it lowers lamp current. This keeps the cathode temperature constant as the lamp cools.
  • Lamp current crest factor (LCCF). This is the ratio of peak lamp current to RMS lamp current. You want less than 1.7 LCCF.
  • Lamp starting. Dimming ballasts need a rapid start, so they should provide 3V to 4.5V at each cathode.
  • Minimum lamp current. Dimming can lower the lamp current from about 200mA to 30mA (some dimming ballasts lower output to 10mA). Over time, the lamp can become unstable at lower currents, as evidenced by swirls or striations.

Source: Mark Lamendola | Mindconnection