Led Lighting issues

Hi all,

Am a noob here and have just installed Cbus in my own home and I am having problems with intermittant failing of my led downlights. Just wondering if anyone else has run into these problems. I am running the 8 channel 1 amp dimmers with no more than 4 ( as recommended by transformer supplier -Sunny lighting ) and the relatively new philips mr12 led master 12v lamps ( Meant to work with 99% of all existing transformers). I have installed Cbus before and all my terminations are A1.
Please help!

 

You haven't said whether it's the lamp failing or the transformer or both. I assume it's the lamps? Can you be more specific, i.e. how many do you have installed and how often are they failing?

Do I correctly assume that you mean MR16, not MR12?

You mention that you're using Philips 12V LED Master lamps. There are quite a few products that fit that description, of varying vintages, and not all of them are compatible with dimming. Can you be more specific?

Which model of transformer are you using? I assume it's an Actec one, but which one? Not all of the Actec transformers are compatible with leading edge dimmers.

The failures are almost certainly nothing to do with C-Bus. The failures may be due to the small bleed current coming from the dimmer channel when it's off. Some of this may make it's way through the transformer to the lamp and causing it to try and operate when there isn't enough power for it to do so.

If you've got a spare relay channel, you can run the output from the dimmer through a relay and assign the relay channel to the same group address. This will ensure that off is completely off. This would test the theory that the failures are caused by a small bleed current getting to the lamp.

If the lamps are the 7W or 10W MR16's that Philips sell, these type have a small rotating fan inside them. Whenever you have a fan of this sort it is susceptible to jamming from dust and grit. When the fan fails, the lamp will blink it's output in a regular pattern. If they overheat, they flicker and flash in a pretty crazy fashion. When your lamps fail, do they just stop working or do the flicker and flash?

LED MR16 lamps are always going to be a band-aid solution for retro-fitting halogen MR16's. The proper solution is a LED lamp and driver that is designed to work together and with dimmers from the outset.

 

Yeah sorry MR 16 10 Watt, probably not the dimmers failing could be the dimmer/ transformer / lamp combination. have seen the lamp fan issue, these light fittings seem to work one minute and fail the next, seems bizzare Philips claim you can use the lamps which are sold and branded as dimmable with 99% of trannies and the trannies are Cbus compatable. Put the lamp in another tranny it works put a standard halogen in the failing fitting and it works fine ( at the time I guess) These Philips lamps are supposed to beyond a simple quick fix. We have not moved into the house yet I have just been picking this up during normal electrical testing. I have replaced 6 of 100 transformers and looks like another six to ten have failed sine energisation. When they fail most just dont fire at all but some will work on one press and not the next or blink on and off slowly llike a flouro trying to fire

 

Sorry to disagree with you but the Philips 10W MR16's are nothing more than a "quick fix". They appear well designed and well engineered but the rotating brushless fan leaves them with a significant reliability liability. They also don't match the output of 50W halogens. With lots of them installed, some ceiling panels can hum due to the vibration from the fans. They'll never be compatible with all types of transformer out there and the compatibility of these lamps with transformers drops significantly if you want to dim them, not just switch them on and off. They have their place in retrofit applications and where space is crucial, but I would not be recommending them to anyone for a new install.

These lamps from Phillips are one of the better offerings for this type of lamp, but the whole product category still has a very long way to go. Making retro-fit MR16 LED lamps that are compatible with all the transformers out there, and all the dimmers out there, is an almost impossible task as the range of variables is very large. There's a lot of active development in this area by dozens of companies, so we can look forward to things improving in the future, but it is a real challenge.

Is the failure mode that, from time to time, they just don't light up? Then, at a subsequent time, they actually work?

If the blinking is regular, then the lamps have had a fan failure. If it flashes erratically, like a fluoro, then the transformer is not getting sufficient/correct loading from the lamp to remain stable in it's operation.

 

The Lamps in my house are failing eratically,turn a switch on and 3 out of 4 lamps fire, then dim up and down, turn off and the one that was off will fire and another will stay dead. also some will all come on then five minutes later 2 wil be flickering then go out. Some just dont work at all. I personally think it may be the transformers not enjoying powering the lamps through the dimmer, I am thinking of swapping out with redbacks. PS have installed the dimmable Osram ES LED lamps (240V) and am hugely impressed with colour (warm white) and functionality.

 

I would definitely try alternative transformers. Fortunately they're relatively cheap, so it would be worth it to exchange a few and see how they go.

 

Newman, do you know if the Osram redback transformers are leading edge cbus friendly? When I say friendly I need to have max 4 on a 1Amp and 8 on a 2.5Amp channel. The rep is telling my wholesaler they are but I have not seen a capacitance in writing. Not that I dont mind changeing 100 downlight trannies for no benefit.

 

The Osram Redback, the current one, has 33nF of input capacitance. Therefore you can in theory connect 9 transformers to a single L5508D1A or L5504D2A dimmer channel. Since the transformers wont' be running 50W halogens, it would be prudent to be a bit circumspect and test this out first.

Just watch out as there are 2 versions of the Osram Redback in the market. The newer one has a red case and a black terminal cover. This is the one you want. The older one has much higher input capacitance.

Since you're driving electronic transformers you will get better efficiency and longer life by runnning the transformers from a Trailing Edge capable dimmer if you can, such as the C-Bus DIN Universal dimmer. You also won't get that annoying buzzing that comes from the dimmer and transformer when a Leading Edge dimmer type is used with electronic transformers.

The redback seems to work really well with the 10W Philips Maser LED MR16. About the only thing you need to do is set a minimum brightness in the dimmer of about 10% to stop them going out completely when you dim to minimum.

 

Thanks mate,

I have wired the cbus boards up using the leading edge dimmers so am stuck with them for the moment, will give the redbacks a shot. OOps the Osram lamps I mentioned were great are actually Crompton.

 

Which Crompton 240V lamps are you referring to. Is it these?

 

Yeah, thats them mate. Your not gonna burn me for using them too are you?

 

Haha, no burning , they are pretty good. They work just fine on the C-Bus Leading Edge dimmers. At approximately 65 lumens per watt, and dimmable on lots of dimmers, the efficiency is excellent.

 

quick fix LED's & better solutions

Hi Anthony
I agree with Newman, any MR16 based LED is a quick fix and will have compromises and will not be overly energy efficient compared to other sources. The Philips ones you mention are the best I've seen on the market (Have a sample one above my desk: rental office). I don't know sunny transformers but the Osram redbacks are solid.

You may also find that you don't need a transformer (Tx) per LED and this may also be part of your issue. Electronic transformers (ETx) are typically rated 20-60VA, so if you only put a 10W load on them you are outside the rated operating spec of the Tx. Try putting 2 or 4 lamps per Tx, this may be a economical solution for you. Keep the Tx output wires away from the mains input wiring. You shouldn't run the output wires of a ETx for more than 2m because of EMC rules.

If you want to do it properly get a purpose designed LED down light. They may cost a bit more, but you will have a much better unit, with higher output and may not need as many per room. They have a purpose built DC driver which is critical to the longevity of your lighting system. Make sure you get a wide beam and warm white 3000K colour (unless you really like blue light) if you are generally lighting a house. There are a plethora to choose from and I have tested many. Many of the more common ones would not satisfactorily dim with only 1 unit connected to a new trailing edge dimmer. The best I've found so far are:
Lumitex Baricade http://lumitex.com.au/products/led-downlights/
LED Lighting EVO50 http://www.ledlighting.com.au/EVO50.html
Both are from reputable companies and I have used the products on commercial projects. Both are about $80ex GST at selected wholesalers. Much better value than the Philips at $38 + Tx + gimbal.

Regards
Matthew

 

Quick fix LED on a Dimmer

I forgot to mention I tried the GU10 version of the Philips (MASTER LED 7W) and the equivalent from Osram at home on my 5508D1A. The dimming was OK but the flicker & delay at the start & turn off was not nice. Maybe they actually act more like a CFL and could use a kick to start them, (like the CFL dimmer clipsal make) has anyone at CIS got a comment on that?

Regards
Matthew

 

The LED Lighting EVO 50 looks the same as the Clipsal LED downlight, which looks the same as the ELR downlight, which looks the same as... several others.

Assuming the above to be true you'll probably find that the light output is slightly reduced when used with 2-wire dimmers, even when the dimmers are set to maximum. You also may find that they don't quite meet their spec in terms of lumen performance. You also may notice some variability in the dimming curve from unit-to-unit.

I'm not familiar with the Lumitex Barricade unit, but nowhere in their literature do they state the hard facts about their light performance, only stating that they are using 5 x 3W CREE LEDs. Not listing the critical parameters of the lamp's performance anywhere would make me nervous. At least they're a member of the Lighting Council of Australia, unlike the other "fly-by-night" lighting companies out there. Maybe that's why they don't state the performance - they know they'll be held to their claims (speculation).

I suggest you try them on a relay channel, to see if the delay/flicker is still there. The dimmer has a soft on/off characteristic and during this time the lamp's behaviour may be a bit undefined if there's only one or two of these lamps on the circuit.

 

I was at the electrical wholesaler today and I bought one of these new 10W models in a GU10 fitting. The kit is made by OSRAM (3000K 10W) and it is trailing and leading edge compatible. I put it as a replacement for the lamp that was there before (halogen GU10). Has a strange dimmer curve but otherwise very bright and very nice.

I plan to put 4 on the same channel as i gradually replace the halogens.

http://www.osram.com/_global/pdf/Professional/General_Lighting/LED_Lamps/_pdf_TI/PRO_PAR16_50.pdf

 

I think the PAR16 lamp format will really be an emerging bulb format in the years to come. LED lamps, particularly 240V ones, are likely to be bigger than their incandescent equivalents for a long time yet. The PAR16 format fits a lot of existing MR16 fixtures and, if the PAR16 lamp fits and the fixture currently has a 240V halogen, it's a straight swap. It certainly can save a headache not having to worry about the old dichroic tranny in the ceiling blowing up because it's being used with a cheap LED MR16 replacement bulb.

A couple things to take not of on the Osram spec. The brightness is only about half that of a typical MR16 halogen, so they're still somewhat behind. They require quite a bit of clearance around them and the maximum operating temperature of 40 degrees is well below the temperature of an aussie ceiling in summer. An efficiency of 37lm/W is pretty old hat these days, even if it is dimmable (which generally lowers the efficiency). They're also quite a narrow beam, so spacing and spread of light may be an issue. A narrow beam, to create a bright centre spot, is what a lot of manufacturers do to fool you into thinking the lamp is brighter than it really is. That front heatsink model is going to struggle to find fixtures that accomodate it.

Still, if you've paid your money and you're happy with them, that's obviously what counts.

 

I would like to indicate that because it is marginally Kelvin hotter than my existing halogen GU10 its light is more neutral. The light is in fact brighter than the surrounding lamps and the beam is amazing for the application I have. It's task is to illuminate the kitchen sink which it does on a gimble at a slight angle. It runs at 10W which is quite huge in LED terms.

The only thing that could play out as unpleasant are the limitations on working temp.

I didnt see any of the illumination problems you mentioned. Though I asked about 4 times if this was the latest model. I presume as most would, that the newest lamps will be the best ones.

Finally after being cycled a few times, the dimming is more linear. I dont know how that this is possible - but it did happen.

 

Guys,
I was being cheap and went for the Cheap Cbus compatible leading edge downlight kits with the Philips mr16 lamps 100 fittings for 4K not 10K for the starburst led downlights I probably should have gone with. Anyhow the wholesaler has looked after me and has given me 100 free redbacks so all I gotta do is change them now then sit back, relax and listen to them hum.

 

About LED's

Hi Newman

The Clipsal & ELR are the same, the EVO does look similar but it's operation is different. It is noticeably brighter than the clipsal (sorry no photometric lab to provide hard numbers, but working on it) but draws 18.5W as compared to the Clipsal 15.2W total power consumption. It dims much better than it as well. The Lumitex it in-between both of these in light output, but only draws 12.5W and dims very well. They advertise 1% on a Clipsal universal dimmer but I have not tested to that level.

They work fine on a relay, two GU10 "retrofit" LED lamps on a leading edge dimmer (5508D1A) wasn't satisfactory for me.