Downlighters
11 June 2002, 10:29 AM
#1
Not sure if this is true, but: I do remember when halogen bulbs first came out, (yes I am that old!), that we were told NEVER to run them on too low a voltage, as it causes the bulb to run cool, with the result that it quickly blues over and becomes useless.
Something to do with the quartz capsule not getting hot enough, and not encouraging the vapour from the filament to go back onto the filament, but to condense on it, rather like a standard bulb does?
Wouldn't this be the effect of dimming them?
Alcazar
Edited to say: Screwfix direct do both mains and low voltage ones at good prices. I have examples of both in my home, and both are no problem, but I don't dim them.
[Edited by alcazar - 11/6/2002 10:31:29 AM]
Something to do with the quartz capsule not getting hot enough, and not encouraging the vapour from the filament to go back onto the filament, but to condense on it, rather like a standard bulb does?
Wouldn't this be the effect of dimming them?
Alcazar
Edited to say: Screwfix direct do both mains and low voltage ones at good prices. I have examples of both in my home, and both are no problem, but I don't dim them.
[Edited by alcazar - 11/6/2002 10:31:29 AM]
05 November 2002, 08:34 PM
#2
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Arrggghhh.
Mains Normal or ...
Mains Halogens or ....
12 V halogens - Electroninc Transformers or Toroidal ???
Need to light a 3m x 4.5m Kitchen. Would like them to be dimmable.
Was Thinking 6 x 35W 12V Halogens with an electronic Transformer
Good Idea / Bad Idea / Experiences ?
Deano
Mains Normal or ...
Mains Halogens or ....
12 V halogens - Electroninc Transformers or Toroidal ???
Need to light a 3m x 4.5m Kitchen. Would like them to be dimmable.
Was Thinking 6 x 35W 12V Halogens with an electronic Transformer
Good Idea / Bad Idea / Experiences ?
Deano
05 November 2002, 09:23 PM
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depends on how bright you want ?
4 or 6 x 50 watt lamps 12 v with individual electronic transformers (better than the bulk transformers)
try the likes of Ross Electrical for something like the Newlec fittings good quality and well priced.
Paul
4 or 6 x 50 watt lamps 12 v with individual electronic transformers (better than the bulk transformers)
try the likes of Ross Electrical for something like the Newlec fittings good quality and well priced.
Paul
06 November 2002, 01:27 AM
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Individual transformers are best, and most are dimmable. Electronic ones will be dimmable. The Low voltage downlighters are also a lot brighter than the 240v variety. The 240v also seem to go through lamps/bulbs at an alarming rate. Not too sure whether they are dimmable, but think they would be.
The most common cause of failure with the low voltage, assuming you are buying reasonable quality items, is that some people when fitting just leave insulation lying on top of them. You must not do this as the heat build up it causes wll cause the lamps to fail.
The most common cause of failure with the low voltage, assuming you are buying reasonable quality items, is that some people when fitting just leave insulation lying on top of them. You must not do this as the heat build up it causes wll cause the lamps to fail.
06 November 2002, 08:54 AM
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Agree with Crypt.
Had ours fitted less than 2 years ago - kitchen and en-suite - and I've had to replace 3 transformers already.
I'd go with mains voltage filament every time.
Cheers
Kav
Had ours fitted less than 2 years ago - kitchen and en-suite - and I've had to replace 3 transformers already.
I'd go with mains voltage filament every time.
Cheers
Kav
06 November 2002, 09:03 AM
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Ta
So its 50:50 LV:Main so far
I guess I need ot check if the Mains ones can be dimmed. I'd rather make sure there was too much light to start and then reduce bulb wattage or dim to get it right.
Deano
So its 50:50 LV:Main so far
I guess I need ot check if the Mains ones can be dimmed. I'd rather make sure there was too much light to start and then reduce bulb wattage or dim to get it right.
Deano
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06 November 2002, 10:45 AM
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Got to agree with Alcazar, I've refitted the kitchen and bathroom using screwfix 12v halogens and transformers. We've a total of 14 lights each on its own transformer. We got one dud transformer which was DOA but after 18 months have had no problems with any of the installed kit. Also, the Screwfix transformers have a soft-start, which improves bulb life.
We're running 8 50watt halogens in the kitchen ( approx 14 foot by 10), plus two smaller ones on the extractor hood. Might sound excessive, but you need really good task lighting in the kitchen, and downlighters produce a cone of light rather than the omnidirectional light from a fluoro or standard hanging bulb, so you need a lot for good coverage.
IMHO you'd be better off wiring for a high power bulb then swapping to a lower output bulb if it's too bright, rather than going with a dimmer. Dimmed lights seem to cast quite a "dirty" colour, presumably because the element's not as hot.
Alternatively you could wire for a full illumination and an alternative low level situation with uplighters, undercabinet lights etc
We're running 8 50watt halogens in the kitchen ( approx 14 foot by 10), plus two smaller ones on the extractor hood. Might sound excessive, but you need really good task lighting in the kitchen, and downlighters produce a cone of light rather than the omnidirectional light from a fluoro or standard hanging bulb, so you need a lot for good coverage.
IMHO you'd be better off wiring for a high power bulb then swapping to a lower output bulb if it's too bright, rather than going with a dimmer. Dimmed lights seem to cast quite a "dirty" colour, presumably because the element's not as hot.
Alternatively you could wire for a full illumination and an alternative low level situation with uplighters, undercabinet lights etc
). Dimming is "nice if possible for odd occasions" rather than the norm.
06 November 2002, 01:36 PM
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dsmith
400W is a lot, but you'd be surprised - it's bright and cheerful, rather than looking like a night match at Anfield!
I made sure that the sparky put the kitchen and bathroom on their own circuit. That way I only run 700W on that circuit in total and also it isolates the halogens with transformers from circuits that carry fluorescent/low energy bulbs.
The transformers warn you not to put any fluoros on the same circuit as there's something in the way the fluoros work that can damage transformers - I wonder if that's why so many people are experiencing transformer failures?
400W is a lot, but you'd be surprised - it's bright and cheerful, rather than looking like a night match at Anfield!
I made sure that the sparky put the kitchen and bathroom on their own circuit. That way I only run 700W on that circuit in total and also it isolates the halogens with transformers from circuits that carry fluorescent/low energy bulbs.
The transformers warn you not to put any fluoros on the same circuit as there's something in the way the fluoros work that can damage transformers - I wonder if that's why so many people are experiencing transformer failures?
06 November 2002, 08:20 PM
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Deano,
Changed most of my electronic xformers after they packed up for the Toroidal type but found that they "buzz" (or mine did anyway)this was particularly noticeable where there were lots of them in the same room, even worse when dimmed.
I have changed back again [img]images/smilies/mad.gif[/img] to electronic, and this time they have been OK (different make) and cheaper.
Cheers
Changed most of my electronic xformers after they packed up for the Toroidal type but found that they "buzz" (or mine did anyway)this was particularly noticeable where there were lots of them in the same room, even worse when dimmed.
I have changed back again [img]images/smilies/mad.gif[/img] to electronic, and this time they have been OK (different make) and cheaper.
Cheers