LED Dimming

[MichaelD]

Just bought and installed my first set of GU10 LED downlighters. I went for Philips 'PerfectFit' 6W 3000k 40degree ones, and replaced a bank of 4 x 50w halogen downlighters.

These things are incredibly white and bright. I'd expected the 3000k ones to be a bit yellower than the halogens, which I'd read are 3100k, but they are actually much whiter, so I can't imagine what the 4000k ones must look like, some kind of dazzling blue-white I guess. Perhaps its the quality of the light, but the LEDs seem brighter, and really bounce light off the white Corian worktop in our kitchen, and seem to give much crisper shadows, probably because the light comes from a single small source.

Dimming with C-Bus2 1A dimmer is very similar to the halogens, I left a halogen in one fitting to compare them, and the LED dims down to almost exactly the same point as the halogen before it goes off, but remains white rather than going very yellow as the halogen does. No problem using 4 on a circuit, no dim light showing when they are switched off, which had been a worry.

I 'd thought I'd just replace one bank of halogens, and use up the displaced halogen bulbs as in the other bank as needed, but I love the quality of the light they give off, so have ordered a set for the other bank.

They are expensive, don't know if the business case really stacks up, but with a bit of 'man maths', these things are a good buy, I paid about £15 each with postage from ebay. No doubt they will be £5 in a couple of years, but having tried them, I had to buy more. Now, about the ones in the hall ....

[21stCenturyElec]

We have tested the Megaman 6W dimmable with the 1A dimmer and they are perfect, we set up 8 on a rig with the full dim range 0-100 and no flicker. We are going to try 12 next when we get a chance.

They cost about £10 each.

We have also been looking into importing direct from the manufacturer the same LED's that are available on eBay by an Australian supplier but they would ship here at around the same price and its hard to gauge the interest, we have tested them and they are very bright!!!!

Ian

[blacky7]

Can't comment on CBus directly. But can CBus output a 0-10V control signal. If it can then you can use a 0-10V RGB Driver/dimmer. This can either be used as an RGB controller when using RGB LED Strips, or as a three channel dimmer for 12V MR16 LED bulbs, or Single colour strips. By using 2 of the channels you could even use the new colour temp change strips (essentially a single strip with both warm and cold white leds). If CBus has a DMX gateway then there are a variety of DMX based LED dimmers/drivers.
We have had some success with Idratek and our 0-10V dimmers and also our GU10 bulbs on an Idratek dimmer module. So if CBus has a dimming module then the GU10 may work. What I would do is check the min load for the dimmer module for CBus, some systems have a min load, some don't and others can be programmed (like Lutron).
As a general note on LED dimming, complete 0 to 100% brightness tends not to happen with the bulbs, its more like 20% to 100%. The strips can be 0-100% but this depends on the control software and how the 0-10V signal is implemented.

Toscal's suggested LED dimming ideas work fine on your CBus networks for LED control and here are the required C-Bus modules that can:

1. Output 0-10V, being the C-Bus analogue output module (L5504AMP) to run third party 0-10V RGB/RGBW LED drivers

2. Output DMX, being the C-Bus DMX gateway module (5500DMX) to interface to DMX equipment / DMX LED drivers

3. Output DALI, being the C-Bus Dali Gateway module (5502DAL) to interface to DALI controlled ballasts/ DALI LED Drivers.

4. Output Leading Edge Dimming, being the C-Bus 8 Channel Dimmers L5508D1A to run 220v/240v LED controllers made to be leading edge dimmed. Great if you can get away with these as they have twice the dimmer density of 'Universal Dimmers' using less enclosure space. Also is the dimmer most people have currently dimming their Halogens in a retrofit situation.

5. Output Universal Dimming, being the C-Bus 4 Channel Universal Dimmer L55082U which can run a larger group of 220v/240v LED controllers, electronic transformers etc. The universal dimmer is the safest dimmer alternative as it detects the load type and selects leading or trailing edge as required (and can also control small motors like exhaust fans / ceiling etc). Downside is only 4 dimmer channels per full width 12 module wide DIN rail slot chewing up enclosures quickly.

All the best,

Blacky7