LED retrofit and dimming

Singapore, 19th August 2014

After a full day of meetings and travel back to Singapore I did not have enough energy to sit down and write my blog last night. I think that after more than 1100 daily blogs (!) it starts to weigh a bit…

Today back in the office in Singapore and confronted, not surprisingly again with dimming issues surrounding retrofit LED lamps (in this case used in chandeliers). It is reaching a stage (as I have mentioned in one of my previous blogs before) that we really have to stay away to try and dim retrofit LED lamps. Even with due diligence testing it still ends up being a lousy dimming action. It may be generally smooth in the main dimming range, but when we reach the lower end specifically we have problems with sudden cut off, not reaching nice glow levels and so on, to the point that it nearly defeats the purpose of having dimming at all. What’s the point of dimming to a level that hardly feels like it is dimmed and then to have a sudden cut off. We need low levels of dimming with smooth and soft fading transitions.

I went to site to inspect it for myself today. In fact the lamp manufacturer had flown in a sample of a patch up dimming component used in Jakarta in the same hotel where it apparently solved the problem; a current loop they call it, not surprisingly a component available from the Chinese market for 10RMB or so. We tested it and lo and behold we can now dim to 1%. It still feels like 10-20% but on the overall it creates a visible dimming action. The only problem we have is that once dimmed down to 1% and then off the lamps only come all on at 20%, there is no smooth fade in. So for now we will be programming the lighting to go down to 1% (not off) and then back up again, that works well. We also rewired the chandeliers to have 3 circuits so we can address them in 3-tiers rather then as a whole giving us more flexibility in setting ambiance levels. While not perfect at least we have managed to contain the problem.

Light watch 5-136: Impressions from site this afternoon.


The chandeliers being installed


Testing the dimming action


Is this really as low as we can go?


The magic component that will “save” us


Looping it on to the dimmer module for testing


Some lights don’t come up when we dim up from zero (testing of the RGB Cove lighting goes on in the back ground)

20140819_154816cThe main dimming power supply board

19. August 2014 by Martin Klaasen
Categories: Light & Learn, light watch, lighting applications, lighting standards | Leave a comment

Leave a Reply

Required fields are marked *

Get Adobe Flash player