Dimming LEDs from

It looks likely that one of our customers with L5112D (12-ch 10A architectural dimmers) are going to replace the existing fittings with dimmable LEDs.

What issues do I need to be aware of and how do I mitigate them?

Eg: I assume that load will be a concern. What sort of minimum wattage do I need to avoid problems, and will S31LCDA fix any issues I have or is it not that simple?

If the dimmers do cause a problem, which product(s) should I be looking at for straightforward reliable dimming?

Note that the dimmer racks are approx 10 years old but otherwise working fine.

 

If you want a reliable solution then I would suggest using C-Bus Dali gateway and then installing DALI LED fittings.
Using the existing Architectural dimmers in fact most phase cutting dimmers (Leading or trailing edge) is a bit of a gamble if it will work 100%. There have been many success this way but be prepared for a lot of trial and error.
31LCDA may help and there are other manufacturers who make load correction devices. Off state or low dimming percentage may cause flashing and is often fixed by have relay channel in series with the output.

 

Funnily enough that was our view and until I went to site yesterday that was what we believed was happening. However the fittings chosen by the client are only available mains dimmed. (I'm just a software guy so I'm just looking for the information to pass on to the sparks.)

There will be DALI for a lot of the surrounding fittings but the question is really whether or not the ones that require mains dimming will work with the existing dimmers.

My thinking (again, as a software guy) the alternatives are:

1. use existing dimmers, with load correction if necessary
2. use new C-Bus dimmers, with load correction if necessary
3. put in alternative DALI/Mains dimming hardware

In all cases the circuits will need cabling back to the DB in the same location, so at least trying the first option would be a good idea. However any tests we can do to find out whether it will work would be a good idea, particularly as this job has to complete in tight timescales.

Any recommendations for hardware for option 3 would be appreciated, and reasons why option 2 would be better or worse than option 3.

 

I have already told them that the existing hardware is leading edge and they seem OK with that.

The dimmers are located in a power room away from the main suite so noise isn't a big concern (and they're not especially quiet now anyway). Unless the noise level is going to ramp up a lot or indicates it is damaging the dimmers in some way, of-course.

 

Ah, missed that. Thanks for re-stating it.

It does all help, to be honest.

The fittings won't be cheap (but that says very little about quality). However what I really need is to know what my best option is if the existing C-Buss dimmer hardware doesn't work. I can either propose newer C-Bus dimmers (in which case I need to be sure they'll be up to the job and that any issues can be put at the door of the fitting) or just ask them to specify their own DALI/mains option and just worry about the control side. Is there any reason to think that a DALI/mains option is going to necessarily be better than a new C-Bus dimmer? (I guess what I'm trying to nicely ask is: Are C-Bus dimmers as good for mains dimming with LEDs as anybody else's kit?)

If it helps, I have now been given some load info. The minimum load on any given circuit would appear to be about 16w (comprising 4x 4w LED filament lamps). I'm not expecting the old dimmers to play nicely with a 16w load, but is load correction designed to help with this or are we still some way out? Most circuits would be quite a lot higher than this, but still not "high".

 

Hey,

For what it is worth, we currently have a number of the Phillips Masterline MR16 fittings running on those dimmers. They dim 'ok' but we did find that we needed a load corrector on them because even with 3 there was enough current to keep them alive. We did find though that the Clipsal ones (Load corrector) were a little undersized for this purpose.

J

 

Even SCR switched dimming has issues with leakage current through the SCR when idle, especially when you are talking about you have an SRC or Triac that is rated at 20-40A, it is expecting to see a fairly high wattage load across it.

 

For some reason I didn't get a notification that there'd been a reply so I missed this useful info until now!

We've proposed tests to determine for sure; we're waiting for them to go ahead.

We're told they are....

That rather depends how they decide to cable it, and the cabling will likely happen before any testing, so it'll be based around 2A/ch max on the basis that the circuits can always be doubled up at the dimmer if we end up using the arch dimmer, but it's much harder to split them later. (The cabling is first fit, but the mains dimmed fittings won't go in until second fit in a few months time; given the tight timescales I'm not optimistic that time will be found for any testing until after first fit.)

 

Hey Mark,

Just wondering how you got on with this?

JB

 

Good question!

We learned a few things but I'm not sure how much it would be wise to generalise from them.

1. For our purposes, L5508D1A (and L5504D2A) worked the best.
2. The DIN rail universal dimmer didn't work very well in any of our tests.
3. The GU10 lamps we tested from a couple of decent manufacturers (Megaman for example) worked well even down to a single lamp without any load correction
4. The G9 and LED filament lamps we tried varied; they all worked but in most cases load correction was required.
5. Without load correction, flickering was the biggest issue but we also occasionally had channels which wouldn't switch off.
6. Tests with the old 12-ch architectural dimmers weren't promising at all - lots of flicker in particular - so we stopped even looking at them fairly early on. (For our purposes retaining the units as functioning spares for elsewhere in the building was more beneficial than cobbling together a solution using them for new LED fittings.)

I have to say that the variation between manufacturers was less than I expected. Cheap unbranded G9 lamps I bought for comparison from Amazon worked as well in tests as the more expensive ones chosen on site (albeit that they probably wouldn't last as long).

Hope that's useful.

Mark

 

Thanks for the feedback.
There are no hard rules with mains dimming LED, every little variation can impact the operating outcome.

 

Thanks for the informative update. Its good to know the different experiences people have with these things!

 

Hi Guys,

Not sure if I'm posting in the correct thread but it's LED dimming related.

I visited a residential site recently that has L5508D1A and L5504D2 installed and the client had Philips MR16 7W LED globe replacements retrofitted about 18months ago. The existing transformers are not a brand I have seen or heard of before (actually don't remember the name) but it appears more than 60% of the transformers are dead, there would've about 50 odd lights all mixed across different dimmer channels. The max is 6-8 per channel. The install is about 10 yrs old so I'm thinking that either possibly the LED lamps are slowly killing the transformers and/or they are just failing due to age.

Has anyone come across something like this? Also wondering what the best method to proceed would be. Whether I replace the failed transformers with redbacks or complete fitting replacements?

 

Are the dimmers L5504D2U or L5504D2A eg universal or leading edge?
If you don't note that and the transformer brand no one is going to be able to give any good advice.
After 10 years and high failure count I'd put those old transformers in the e-waste bin anyway.

Here is an old dimming chart.
http://www.cbusforums.com/forums/showpost.php?p=13070&postcount=22

Using those Philips LED's is contrary to the recommended minimum 70% loading for electronic transformers.

Pierlite Starburst Crystal ECO 3000K, even the low output 1st gen version are going work beautifully and have a higher lumen output rating than those Philips LED's.
They have specs for various CBus dimmers and if you follow the specs I'm confident you can expect a great result.
They are claimed to dim down to zero and that has been my experience.
You should check the dimmer min max settings if they were set up for the Philips LED's.
http://www.pierlite.com/au/87173/starburst-crystal-eco#.WTSZEmjfpaQ
http://www.pierlite.com/download.php?id=89393&filename=Dimming_Compatibility_Apr2014.pdf

 

They are L5504D2A, the old transformers are ILD Brand - Model ET60
I've uploaded an image.

I agree, I think the old transformers are ready for the bin.

Thanks for the info
I'll check out the starburst you've suggested as a Replacement

 

1A and 2A leading edge dimmers.
I haven't tried the Pierlite Starburst Crystal ECO LED's on leading edge dimmers but they do have specs for those.
Min 3 per channel.

Talk to Pierlite and your supplier about options if the home doesn't match the specs.
Maybe 31LCDA load correction device can lower the min.
I hate to use them, one because they cost money and two because it seems a convoluted way to have dimming LED's on site but it could be an option to consider if you need it.
Ask the manufacturer and your suppliers to confirm that solution as well.

Don't take any of the risk upon yourself that the products will work as intended.
Pierlite supplies specs.
Stick to them and worst case scenario send them back if they don't work flawlessly.

Starburst Crystal ECO's are a nice product.
Hunt around for pricing, they are not the cheapest thing out there but not too ridiculous either.
Especially since they come with specs for CBus and have super low dimming levels.
The Gen 2 versions I haven't used but wow the lumen output has jumped significantly.

 

I have been using Haneco Viva110 LED downlights with great success on 1A and old D750 C-Bus leading edge dimmers for some time. On the weekend, I tried the Haneco VIVA110-MULTI (this is a fixed downlight with a 3 position switch for installer selectable colour temperature). Typical buy price for these is about $13.00 +GST for day to day purchases. They work brilliantly! No flicker and dim down to low levels (well as low as the dimmer's minimum conduction angle will permit).

Cheers