Perth, 24th February 2011
One of the latest issues we are now facing as lighting designers is the compatibility of LED lamps for dimming. Though many lamp manufacturers claim their lamps are dimmable it seems that actual dimming capability varies from manufacturer to manufacturer. We are facing this issue now as we are retro fitting some incandescent lamps with their LED equivalent but find out that flickering occurs in the lower dimming ranges. It seems that the big LED lamp manufacturers are aware of this but obviously not very expressive in highlighting this issue to us as designers. We are finding out the “hard” way, specifically when it comes to professional dimming systems.
One of the reasons seems to be that the dimming technology of these systems is still based on good old halogen lighting. Meanwhile back in the factory the manufacturers research teams are frantically trying to catch up with the ever evolving LED technology to find compatible dimming technology!
We found that one of the issues is loading. Dimming a simple 2 or 3 Watt LED causes the lamp to flicker when dimmed low, but as soon as there are a few dimmed together and the combined loading rises to 20 Watt or so the problem disappears…interesting, right? But then again during tests we found a 12W LED E27 retrofit turned out not to be dimmable with the selected dimming system but its “older” 8W brother was dimmable without problem?
My message today is: ”check out your dimming compatibility!” Most lamp manufacturers are aware of the issues surrounding dimming of their LED’s and some of them have even a list of the dimming systems that they have tested their lights with. In my case now I have to make a judgement call. Changing the LED lamp manufacturer brand may not resolve my problem and vice versa selecting another dimming system neither. So based on the actual test results I will delete one dimming circuit where I feel the high performance is more important than the ability to dim and in the other case I will have the dimming programmed to cut off to zero when flickering level is reached as I am satisfied that the lowest (non-flickering level) is acceptable. No one will know… 🙂
In Light Watch today the twilight time of the day, the time at dusk when the sun has disappeared (or dimmed down so you want) and night time takes over or vice versa at dawn when daylight emerges…
Light Watch 39: Twilight in Jakarta, Indonesia