The demise of the fluorescent tube

[kalee20]

Originally Posted by 1100 man

The question of colour temperature is also interesting. For me, 4000K is as cool as I feel comfortable with. I find being in a room lit with 6000k light really horrible. I've read that sufferers of SAD need 6000K+ light, but to me it's just chill and depressing.

Surely 6000K is warmer than 4000K? The hotter a black body, the bluer the light? I've always been puzzled by the reference to yellower light as 'warmer' than bluer!

Originally Posted by 1100 man

I agree that the whole CFL thing was utterly horrible. We were forced into them on the basis of energy efficiency, but I'm sure if you take the manufacturing costs, toxic materials, almost universal disposal into landfill and often very short lifespan into account, then we would have been much better sticking to incandescent until LED's came along!

I agree! I really don't like CFL's. However, it's just a case of hindsight, and backing the wrong technology. LED's were a lab curiosity for a while, then came available as indicators. It's comparactively recently that light output has been sufficient for lighting. At the time of 'going CFL' there was the hope that a succession of improvements would take place, instead, it looks as though what we ended up with 10 years ago is as good as it gets, whereas the LED people have found ways to just get better.

Fluorescents and LEDs for lighting do have one thing in common - they both rely on fluorescence (in the fluorescent lamp it's excited by UV from mercury vapour, in the white LED it's by blue light emitted from a diode structure. So I daresay that all the work that the chemists did to make better phosphors has been used by the LED people. The effort hasn't been wasted!

[Maarten]

Originally Posted by G4YVM David

Really? I know that's why floors were banned in lathe workshops but I am surprised LEDs also strobe.

Especially the cheaper ones, even if they have switch mode power supplies. Using a smaller than ideal mains smoothing capacitor was apparently deemed a good way to reduce budget (not only the cap itself, but also through reduced power dissipation everywhere else).

[ianj]

I might retrofit a flourescent tube light in my kitchen , but fit the modern led tube instead !

[The Philpott]

From pure curiosity, yesterday I saw one on-line outlet charging £60 per 8' tube (whilst another was charging £15- but a minimum order of 5 units)
Reading between the lines the message from the former outlet was apparent- if you want something this long and fragile, 'phone and negotiate a discount, then come and get it yourself. (..with a cardboard tube from a carpet warehouse) Fair enough really.

I can't remember the last time i shifted an 8 footer without clonking it against something- and wow, are they stronger than they look!

Dave

[Station X]

Originally Posted by Station X

My CNC lathe has a lamp, I'm not sure what type, inside the cabinet. As the chuck comes up to speed it appears to be stationary, run backwards etc. There is no danger though as the cabinet door has an electro-mechanical interlock and cannot be opened with machine running.

Just checked it. It's a 'U' shaped fluorescent tube about a foot long. Never seen one like it before. I'd better get a spare now while hopefully they're still available.

[electronicskip]

A lot of those expensive professional makeup lighted mirrors use the small circle tubes, so I wonder if a viable replacement is available?

[Sinewave]

Originally Posted by 1100 man

Can I have 6 off, 6 foot twin fluorescent fittings please? High frequency ones.

-Sorry, we no longer stock those.

Oh, how about a single 5' one then?

-No sorry, haven't got any of those either!

I'm wondering if that's just at the store you went to, as I can still get the regular tubes and fittings from the usual places around here.

[emeritus]

A few months ago I bought a selection of GU 10 LED lamps of various beam angles and wattages for a new outside light. Those by Pro -electric flickered, those by V-Tac and Megaman did not. Interestingly, in very small print, the boxes of the V-Tac lamps warn that they should only be used for 10-12 hours daily, and that usage for 24 hours would void the respective 2 and 5 years warranties. Just.as well I will not be using them in a "Dawn to dusk" application where they would have to operate for more than 12 hours per day for around half the year. Both have a nominal 30,000 hrs life, and 5 years is more than this, but 2 years is only about half this on my rough calculations. The other makers do not mention any limits on daily use.

[The Philpott]

Sylvania 'Activa' tubes were a little disappointing. More expensive than the standard article (cos of multiple phosphor layers presumably)

Claim 5,300k but it comes across as a slightly sickly light green. Less efficient as well; on the alpha efficiency scale we are used to seeing they were given a B when the other T8's had an A. I might give them another try from the SAD point of view before condemning them, but i'm not convinced.

Dave

[1100 man]

Kalee20. "Surely 6000K is warmer than 4000K?". I've never thought of it that way but I sort of see where you are coming from! The warmer a black body gets, the higher frequency the radiation will be, so nearer to the 'blue' end of the spectrum.
In human terms though, we perceive warm to be at the red end of the spectrum which is where the heat from the fire is!

The Philpott. 8' tubes were discontinued many years ago but seem to still be readily available but at insane prices!
I still have a stock of them and in fact changed two last weekend in a factory. Considering how thin the glass is, they are amazingly strong- I too have whacked them while carrying them and not broken any!
I have another few to replace for another customer next week. I believe there used to be a 10 foot tube, but I've never seen one!

Sinewave. " I'm wondering if that's just at the store you went to ". This is a large electrical wholesaler to the trade where I've had an account for some years. A big chunk of the local trade will shop there, so if they are no longer stocking fluorescent, it's a fair bet that other retailers will follow suit in the near future.

Well, I've taken the plunge! I have a 5 foot LED fitting to install in the guy's tea room at the weekend. It's a 40 foot 'Portakabin' and has two other 5' fluorescents in there already. I'll be interested in how the new fitting compares!
Watch this space!

All the best
Nick

[julie_m]

Every discussion forum needs to have a focus, otherwise it ends up with discussions about anything which peter out into discussions about nothing. And then it starts losing readers. The Internet is a big enough place already. If you want to talk about cars, then do so in your own bit of it. Links to private blogs are allowed here, and almost certainly preferred to off-topic posts.

Back on topic: LEDs are a technology I have seen mature in my own lifetime; from dim red indicator dots in the early 1970s, progressing through the spectrum in the 80s to blue and violet by the 1990s, and getting brighter with each iteration. The colour rendering has also improved vastly since the early bluish whites.

I'm replacing my CFLs with LEDs one by one as they fail; but it's going to be a rather slower process than the original process of replacing the original tungsten filament bulbs with CFLs!

[The Philpott]

All my CFL's are sitting in a box in the loft, wondering what the hell happened.

'the lamps in this luminaire cannot be renewed' for LED fitments is a retrograde step ecologically and i hope that the ES/BC sockets will go on and on. (Sooner or later someone will crow that they are hazardous- but if someone wants to stick their finger in a light socket perhaps there isn't much hope for them in the long term..?)

I have just found a pair of 125w tubes in the loft- perhaps i will get a suntan this year after all.

[paulsherwin]

I can certainly see CFLs disappearing from general sale soon. Even people who don't mind them are likely to have a lifetime's supply of the things in a box somewhere, and will never need to buy another new one. Quite apart from the vast quantities sent out by the energy companies, you often see bags of them put out by the roadside by people who have switched to LEDs.

[russell_w_b]

Originally Posted by The Philpott

'the lamps in this luminaire cannot be renewed' for LED fitments is a retrograde step ecologically...'

Indeed. And the thing that governs the life of LED replacement bulbs is not the LEDs but the electrolytic capacitors contained therein. The manufacturers haven't yet caught on to the fact that the lamp they claim to have an optimistic life-expectancy is only as good as its weakest component.

So why aren't LED replacements made with detachable control circuitry like the industrial specced-CFLs, conventional fluorescent tubes and other discharge lamps are / were?

[emeritus]

Probably down to manufacturing cost. A two-part lamp with a detachable, customer-replaceable, light-emitting element would need a connector that would increase its cost. I remember when I was with Plessey that you could get a complete Shure cartridge for your Garrard deck from the staff sales shop for considerably less than the cost of a replacement stylus from a record shop. By the time you have factored in the middleman's costs, there would probably be little retail price difference between a one part lamp and half of a two-part lamp.

[Paul Stenning]

There would also be compatibility and customer confusion issues, because every manufacturer would have different connector types, and variations of those for different lumen levels etc. It would also make the overall unit bigger to accommodate the connector. They would also need to design the power supply part to not fail if run with no load.

When it stopped working the customer would have to somehow work out which part needed replacing, find and purchase that (if still available), fit it together and hope for the best. Chances are they would buy the wrong part, or a different brand or lumen level and it wouldn't fit or wouldn't work.

When the whole lamp only costs about £2 it just isn't worth the bother. It is a single replaceable item like the filament and CFL bulbs they replace, and in reality they are reasonably reliable and long lasting, even if they don't achieve the claimed 25,000 hours or whatever.... if anyone is counting!

[kalee20]

True. And even with the BC CFL's, you have to place the whole plug-in item when it stops working. You can't replace just the tube, or just the power supply, if that fails.

Traditional fluorescent lamps, you can replace just the tube, or just the starter. In principle, you could replace the choke, or the power-factor correction capacitor (if fitted), but I've never heard of anyone doing so - they just replace the whole fitting.

[russell_w_b]

Originally Posted by Paul Stenning

There would also be compatibility and customer confusion issues, because every manufacturer would have different connector types...'

Once the transitional period through incandescent. fluorescent / CFL / LED is complete I don't see why a standard ceiling rose arrangement could be designed, produced and churned out like any other electrical fitting. This would then become a repairable (as appears to be the current mindset) or replaceable unit, as and when necessary. As for standards, every lamp manufacturer and their uncle made bayonet caps and ES by the shed-load for years which evolved into something pretty universal.

Originally Posted by Paul Stenning

When the whole lamp only costs about £2 it just isn't worth the bother.

But it is! It's no good folks bleating on about the environmental impact of the end product in their homes or industries when they're turning a blind eye to the cost of manufacturing and carbon impact it has. Oh, OK then - a balance has to be struck. The cost of producing an incandescent lamp from some sand, a paltry sheet of tin and a bit of tungsten is environmentally cheap but the cost of running it far outweighs any production costs. So a similar balance must be struck between churning out capacitors or other components, plastic (currently deemed the enemy) and the cost at the other end of running the things. But it's certainly not insurmountable.

[russell_w_b]

Originally Posted by kalee20

True. And even with the BC CFL's, you have to place the whole plug-in item when it stops working. You can't replace just the tube, or just the power supply, if that fails.

The CFLs we used at work in our radio transmitters had separate ballast units and we just used to stock up on the tubes, of which we have plenty kicking around, no longer needed. Just as well we had plenty as they were rubbish in high-power radio transmitters, and would light of their own volition, shortening their lives dramatically.

The thing is money could be saved in the long term if domestic consumer products were designed along the same lines as those used in industry.

If I could find a long term reliable LED lamp I would be happy to spend a bit more, all so far are the same cheap construction and component quality. Poundland do good 5W ones that (so far) have outlived some £8 Philips ones.