LED MR 11 lamps

[Derek ^]

Some imported dining room furniture we've got came equipped with top lighting in 4 display cabinets. The electronic transformers have all quit and the lamp fitting itself takes a 10w capsule bulb mounted sideways on in a very shallow fitting. It is *absolutely impossible* to replace a bulb with the fitting in the top of the units without either bending the pins or touching the quartz. If you do bend the pins IME the bulb will have a short life even if it works initially.

So I went to "Ring" lighting and came away with a set of 20 watt MR11 downlighters @ 3 for 8 quid in their discontinued section.

On reading the bit of paper that came packed inside it says they should not be mounted on a combustible surface. The display cabinets are made of wood. :-(

I then noticed that LED MR11 lamps are available, less than 2 watts so not a fire hazard. £7.50 each, (I could live with that if I never had to change one again!) but on the websites that sell them they say ordinary transformers can't be used, the special electronic transformers needed are £14.99 each. That's taking the Mick. Surely 12 volts, 2 watts to drive 6 LEDs, an ordinary regulated mains adapter would fit the bill or am I missing something here? Apparently the LED lamps *are* AC/DC.

Oh, and BTW the electronic transformer that came with the RING lighting kit is duff. :-((

DG

[Andy Dingley]

So touch the quartz. This is a much over-rated risk these days (so long as it's not a microsocope lamp or something that really does run hot). If you wash your hands first, it always was an over-rated risk.

Always a mistake.

I've disappointed in all the LED MR11 lamps I've used so far. Just about the only thing I would consider using them for would be display cabinet lighting - as room lighting they're dismal. Be careful though that their output angle is suitable - most of them gain their high brightness values by having a narrow output.

I've not seen an LED MR11 that wasn't compatible with "typical" 12V low voltage lighting transformers (although most are DC only). They didn't need anything special, although some PSUs can be unhappy because the power demanded is too _low_ (they see this as not having any bulbs connected)

Volts is volts. If you know what they need, and you can arrange something to supply it, then go to it,

You bought a Ring product. Just be grateful it didn't try to kill you.

[Andrew Gabriel]

I either hold them with a piece of tissue, or if they're in a polythene envelope (e.g. Maplin's ones, which are also the cheapest sine CPC stopped selling them) just cut the end off the polythene which I use to hold the lamp until it's in the holder.

Bare in mind that LED's are same efficiency as halogen lamps, so these will give off the same light as a 2W halogen would have. This might be concentrated into a very narrow beam so that on-beam intensity is high, but unless you want that feature, they are generally a disaster.

LED's need current limited supplies. It depends if the lamps themselves contain the current limiting function, or if they require the supply transformer circuitry to do it. Both types exist, and the ones with external current limited supplies are likely to be brighter, as that potential heat source is removed from the locality of the LEDs.

My impression is that Ring source cheap, rather than high quality parts. I've had some good Ring items, but also some extremely poor ones.

[Matt]

In the early days of compact fluorescent's I bought a few of their lamps, the first one I fitted worked for maybe 5 seconds and then tripped the (6A) MCB. A short while later the lamp made a *very* loud bang with the lamp base getting extremely hot to the point at which it could hardly be touched a minute after the MCB had tripped. The plastic distorted slightly and didn't melt but you could tell there had been a huge amount of heat dissipated internally.

I'd bought them via Farnell's and found it quite strange that they gave an immediate refund without question pending their later return. A few weeks after returning them I got a phone call from Ring asking for more details about the fault. This started off quite friendly but went rapidly downhill then they mentioned they had found no manufacturing defect and more or less blamed my installation for causing the failure! - one that had previously worked perfectly with an incandescent 60W for two decades. A Philips CF replacement worked in there for another 5 more years.....and Farnell's stopped selling Ring lamps.