Q & A of the Day – Can you dim fluorescent and metal halide lamps?

Question: I need to know more about the dimming of fluorescent lamps. Exactly how do 0-10V and 1-10V systems work? Does it provide energy saving? If so, how? Also, is it possible to have a addressable dimming system?

I would also like to know whether, in a similar way, metal halide lamps can be dimmed? If not, why not? I did find a website of a company selling dimmable metal halide ballasts.

I would be very thankful if you could answer these queries and supply in-depth information regarding dimming and dimming systems.

Answer: 1-10V analogue is an industry standard dimming system. Osram ballasts provide 1-10V products, and an external pot is needed to sink a small current. This will alter the tube current but will maintain the cathode current at an optimum level. Varying the tube current will result in dimming of the tubes.

Dimming with Osram control gear will achieve proportional energy savings. See the attached graph.

For addressable dimming you will need to move from analogue dimming to Digital Addressable Lighting Interface (DALI) digital dimming. In each ballast is a processor that remembers the dimming level and the group it belongs to.

Dimming of metal halide lamps is not very practical as the lamps will exhibit severe changes in colour temperatures. We do not recommend that our lamps be dimmed.

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