Lighting-Gallery.net
Lamps => Vintage & Antique => Topic started by: Roi_hartmann on May 10, 2010, 03:30:30 PM
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Hi.
Today I found some old Airam 40W T12 warmwhite deluxe lamps but what is weird is that those are approximately 100cm long and not the typical 120cm. Is this some T12 version of modern 30w T8s or what? Those had that older airam logo so they dates pre 70s. Unfortunately my camera is broken right now so no pictures yet. What kind of ballast should I use to run those? I have to see if I can find some more of those next time.
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Yes, there is 970mm 36W 0.556A and 1047mm 38W 0.43A T8's. The first need special ballast, not common with any other fluorescent due to different current rating, the second will run on generic "36/40W" ballast.
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thats bad luck.... :( those are exactly those 970mm long lamps. There was actually this number printed in the etch and I first thought that would be the colorcode or something. Now, for what purpose these lamps were made? is it some old standart or what is the story behind these "special" lamps? I should probably go to check if there were any ballast for those lamps(found them in one demolition site) There were some fixtures but those were so weird shaped and ugly so I did not investigate any closer. There were huge bunch of these lamps but there is not much joy of these if you dont have a ballast to use them... Thanks for help anyway.
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I think the 1 m lamps are mainly used in outdoor signs, at least that is the only place where I have seen them. The tubes are still available today, even 40 W T12 (at least at my supplier). I think this is because T8 drops to much light output at low ambient temperatures.
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I checked Helvars catalog and there is ballast for 36w lamp with lamp current 0,53A so that kind of ballast is probably meant to use with these lamps(anyway the lamp current is very close). model number is L 42 T6 but getting that kind of ballast is probably not an easy thing to do. I have to go to do some dumpsterdiving to find out if I can find suitable ballast.
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I just recalled from my memory: 0.5A are 35W MH, 0.6A are 50W MV. These are not so far from the 0.55A, so you might use this ballast, but in preheat circuit, of course. I guess these HID ballasts are usually less lossy, so you will get higher efficacy then from "fluorescent" ballasts
Or it would be at least good experiment to use the HV MH ignitor as instant start setup...
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I went back there but the fixtures were gone. There was still some lamps thought and I found similar coolwhite deluxes. I have 50MV ballast somewhere so it will have to do.
@Medved: Yep, with HV ignitor you could probably make nice lamp tormentor ;D. I have one 4,5kV hps ignitor but its sure that I wont try it with these lamps. Maybe some less valuable lamp could be tested with that kind of connection. How much is the ignition voltage in instant start ballast? I bet way less than 4,5kV
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I know Thorn Lighting still make 1 meter fittings which are now 38W T8s but I can't find any other manufacturers that make them. It seems to me like the 1 meter lamps were a failed attempt at creating standard metric size fluorescent lamps.
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Based on what I've heard and read, the 36W-1 T8 and 38W T8 tubes were created for European (only?) shops with specific shelf lighting which have certain standardized shelf widths. Neither the 30W T8 (90cm) nor the 36W T8/40W T12 (120cm) matched the width of these shelves so that is why the inbetween-length 36W-1 and 38W T8 tubes were introduced.
Actually, the 36W-1 and 38W versions were the successors of the T12 versions 40W-1 T12 and 42W T12 that came to the market at the end of the 60s. I still have a Philips 42W color 33 T12 at home from that era.
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Ahaa, Thats interesting. How do the construction of these 40W-970 differ of standart 120cm long 40 watters? probably those have different cathodes but is there something else different?
I was just thinking what kind of changes they had to make to get same wattage for shorter lamp.
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Ahaa, Thats interesting. How do the construction of these 40W-970 differ of standart 120cm long 40 watters? probably those have different cathodes but is there something else different?
I was just thinking what kind of changes they had to make to get same wattage for shorter lamp.
Simple:
Heavier electrodes. And shorter length mean lower voltage drop automatically, this was actually compensated by increasing the rated current.
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I'd just run a 40W-1 tube on a 40W-1.2m electromagnetic ballast...
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I'd just run a 40W-1 tube on a 40W-1.2m electromagnetic ballast...
Then you run it only at ~30W. I think it is not anymore healthy for electrodes, as they can run too cold (without auxiliary heating), so their emission may not reach required level to avoid sputtering.
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The lamp will indeed run at reduced power but I expect the lamp current to stay at or slightly above the minimum required level needed to keep the electrodes sufficiently heated.
There a few alternatives however tht will run the lamp close to nominal power:
Find the correct ballast (tough to find)
Use 2 ballasts for European TL25W T12 (0.25A, 100V) in parallel
Use 2 ballasts for PL-C 26W (0.3A, 80V) in parallel
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In Europe, this 970mm 36W T8 lamps are still in production (Osram), you can buy it. These lamps need also a higher preheat current of 0.73A. I've 36W-1 and 40W-1 lamps in my collection.
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The ballast in one of the 4ft 40/36W fluorescent lamps in my garage says that it can be used with 1x 1200mm 40/36W, 2x 600mm 18/20W and 1x 1050mm 40W fluorescent tubes. The current rating on the ballast is 0.46A which is the same as every other 4ft 40W ballast except this one says it's compatible with with the 1 meter (or 1050mm) tubes.
I'm guessing you should just try this tube on a normal 40W ballast then!
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@Eliot_240: But the lamps I had found are 970mm long so as Medved said the lamp current of those would be 0.556A wich is more than "standart" 36/40w 0,43A
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Sorry, I didn't check the measurements of the lamp in this thread properly before posting! I don't know what the 1050mm long lamps are at all then.
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The PL-L 55W & F54T5/HO are in 460-530mA range. Ballasts for these lamps are accommodating of wide range of lamp voltage and OCV doesn't really matter as long as it isn't too low as they're all programmed rapid start. Filaments are heated first, then arc voltage is applied, so you don't really have to worry about lamp instant starting which was a problem with "rapid start" electronic type that applied arc voltage and filament voltage at the same time.
These ballasts should be readily available.
PL-C is a 320mA design, so a it'll work on a PL-C ballast, but will be under-driven.
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Generally saw metre tubes in fridge-freezer cabinets in supermarkets in the 70s and 80s both here in the UK and in Europe, but certainly never used for other purposes such as domestic, etc. Europe never switched from the standard imperial lengths because this would be costly for everyone involved from manufacturers having to explain this to stockists and users, stockists having to double their space to house two different sets of tube lengths; confused members of the public buying and returning "wrong" length tubes or worse still "adapting" standard luminaires to accommodate metric lengths irrespective of electrical compatibility.
This was an explanation I once received from a rep from an unnamed company whilst working in the sign industry at a time when signmakers began switching to metric sizes.
Back to lamp lengths, the only metric size was the one-metre as far as I can recall, but it just so happens that the standard five-foot is a metre and a half long!!!!
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/Filaments are heated first, then arc voltage is applied, so you don't really have to worry about lamp instant starting which was a problem with "rapid start" electronic type that applied arc voltage and filament voltage at the same time.
This is true only on some ballast designs (only those using PTC for preheat control and/or series choke with electronic starters).
All other do apply voltage across the tube during preheat phase (try to touch the "hot" side, it will glow), while this voltage is supposed to be too low to ignite the discharge in the designated tube. But if you connect tube with the striking voltage below the voltage during preheat, it would start prematurely (in fact as RS). On some dimmable ballast (mainly based on the the IR21592/3 chip) this would be a problem, as the state machine in the controller would not see the current pattern expected to signal the lamp ignited, so it would fall into FailureToStrike error mode (so shut down the lamp)
It is consequence of how these ballasts work: During preheat the lamp LC circuit is only operated further from the resonance, so there flow enough current to preheat the lamp (in the current mode preheat circuit) and/or the voltage on the inductor is quite high (in voltage mode preheat circuit) to heat up the filament, but the voltage is not sufficient (with margin) to strike the discharge. When it is supposed to ignite the lamp, the frequency start to sweep down towards resonance, so the voltage rise till the lamp ignite. And as the lamp ignite, it damp the LC tank, what reduce the voltage boost, so all voltage and currents (mainly trough the capacitor) in the circuit drop, what reduce the heating power to negligible level (so it could be stated, then it in fact stop heating filaments).
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This was the first attempt at making a metric tube, introduced in the 1970s, with a length of 970mm so as to realise a 1000mm long fitting. It was a commercial failure and really did not take off. Part of the reason was that its efficacy was much lower than the standard 4' 40W tube and it needed a new higher current ballast which was rather large.
The second metric tube was the 1047mm 40W T12 (actually 42W) introduced in EU by either Philips or Osram, I am not sure who was first. This was more logical because it was developed to suit the standard 600mm metric ceiling modules, which are slightly too short to accept all of the imperial length tubes except the 6' length. However the 40W T12 1047mm tube was also slow to be accepted because its efficacy was about 10% less than a regular 4' 40W T12, and it needed a new and large ballast.
The problem was elegantly solved by Thorn who invented the 1047mm 40W T8 (actually 39W) in 1975. The change of glass diameter increased tube voltage to almost exactly the same level as a 4' 40W T12 so that the same ballast could be used - and efficacy also matched that of the imperial version. That was the first metric tube which really made sense and achieved much better success for a number of years. More recently, the tube was re-named 38W (although it still in reality consumes 39W). The same tube is also sold in a U-bent version 525mm long, for use in single 600x600mm ceiling modules.
Today these metric T12 and T8 tubes have almost completely disappeared, except for replacement purposes. The long-standing problem of metrication was solved by the modern T5 long tubes, whose lengths are all about 5cm shorter than the imperial tubes to enable their compatibility with 600mm modular ceiling systems.
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F40T12 is metric too. Length less pins is 1200mm rather than 48.0".
There is also a strange lamp that is designed to utilize the same ballast but shorter by exactly 4cm called 40W/1160mmT12/RS