low voltage dowlighters

I intend to install 9 micro 35mm downlighters in my lounge. I have an existing ceiling rose but want that to be taken out as I am having the ceiling replastered. I will order 9 lights and 3 60w transformers. The lights take 20w bulbs.

Would the best way to do this be to simply connect a 3 way junction box to the circuit above the ceiling and take the three spurs to each transformer and then the corresponding 3 lights or is there a better way of doing it.

look in the reference section, wire the transformers in paralell

I didnt find reference section that helpful without diagrams

I was thinking of buying 12 lights now at 20w each

Is it better to run these off two 150w transformers. Or one large one. Or say to run a 60w transformer for every three lights. I am thinking of cost as well as lamp and transformer life.

I would have thought a 60w max transforer would be tight for for 3 x 20w lamps.

sorry didn't realise the refernece section you meant

thanks

mclaycm said:

Is it better to run these off two 150w transformers. Or one large one. Or say to run a 60w transformer for every three lights. I am thinking of cost as well as lamp and transformer life.

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It is better to have 12 small transformers; one per light.

It is far better still to have no transformers and use mains halogens....

one nice setup i have seen before is elv halogens clamped onto a pair of bare metal bars

It is better to have 12 small transformers; one per light.

It is far better still to have no transformers and use mains halogens....

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a) Mains halogen give you approx 30% less light watt for watt vs 12V
b) Mains halogen lamps generally last on average 1000hr opposed to a "branded" 12V 50W halogen which will give you between 2000 and 5000hr life
c) Dimming 12V sets is much more straight forward than the old "reduce by 25% to 50%" mains halogen.
d) 12V lamps are half the price of mains halogen lamps to replace.

so, what are your arguments for mains halogen again?

treacleman said:

a) Mains halogen give you approx 30% less light watt for watt vs 12V
b) Mains halogen lamps generally last on average 1000hr opposed to a "branded" 12V 50W halogen which will give you between 2000 and 5000hr life
c) Dimming 12V sets is much more straight forward than the old "reduce by 25% to 50%" mains halogen.
d) 12V lamps are half the price of mains halogen lamps to replace.

so, what are your arguments for mains halogen again?

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a) Not always true. Different manufacturers at different price points quote different figures. In both cases it's a spread of ratings with a lot of overlap. Some mains halogens are more efficient than some 12v ones, and in a lot of cases the differences are so small that if you were concerned about them you'd not be using halogen lighting in the first place.

b) Not always true. Different manufacturers at different price points quote different lives. In both cases it's a spread of lengths with a lot of overlap. Some mains halogens are longer lived than some 12V ones, and in a lot of cases the differences are so small that if you were concerned about them you'd not be using halogen lighting in the first place.

c) I disagree - you still have to select an appropriate dimmer and you also have to ensure that the transformer is suitable for dimming - more complication, not less. And even then, there's a reasonable chance that the transformer will generate an annoying buzz when dimmed.

d) Not always true. Different manufacturers and different qualities result in different price points. In both cases it's a spread of prices with a lot of overlap. Some mains halogens are cheaper than some 12V ones, and in a lot of cases the differences are so small that if you were concerned about them you'd not be using halogen lighting in the first place.

Additionally, good quality transformers are not cheap.

Finally - future proofing. LED lamps are getting better and cheaper all the time - they're already up to 20-30w equivalence, and the hugely increased life already more than compensates for their higher price. With mains luminaires you can just plug them in. With 12V ones you'll run into problems with underloaded transformers, as the actual consumption of these lamps is in the 1-2W range.

i am waiting for the multi coloured changing led lamp (not single led) that you decide what colour it will be.

Why do you want to get changed by the light of a multi-coloured LED?

Is it so that Mrs Breezer can't see what she's getting?

i have seen similar done with dmx operated lights, and decided it looked quite nice, but they are a bit big

i remeber seeing a small muti perpose stage at an exibition that was lit entirely by dmx color mixers on 2 axis motorised mounts

also i've always wondered why par36 unlike most other par types is 6V elv and uses screw terminals on the bulb

Just on the topic of LED lights i went down to B&Q today and spent quite a bit of time looking in the light section. They have got quite a large variety although the prices are a bit steep i think.

Decided to open up the LED light sets (soon put them back in though) They are a recipy for going wrong with all those small connectors etc. Having said that it has left me with a couple of questions.

1) Can 9V DC PLUG IN ADAPTOR ever be done away with by connecting the wires to a light switch instead so you wouldn't have to plug it in.






The features are as follows:
The latest lighting technology is LEDs (light emitting diodes), these allow you to add light in new and interesting places

These are funky and great fun so kids will love them, but they are not just for the kids

Add to skirting boards, staircases, bedrooms, living rooms and outside in decking

Dimensions: (H) 27 x (W) 15mm

Super bright LED

Are they really possible to be connected to mains lighting in any way at all, so that the wire to the plug isn't showing etc.

yeah you plug the tranformer into a hidden socket controlled from a seperate switch

many people frown on putting 13A sockets on lighing cuircuits but i have done it in my own bedroom and i don't know of any regs prohibiting it