Obsolete fluorescent light fittings

[Herald1360]

Bayonet fitting tubes often just hung between a pair of dangling bayonet sockets so no problem fitting each one separately. More sophisticated lumieres would clip the tubes to the fitting, but still have flexible leads to the bayonet sockets to enable them to be fitted to the tube rather than the tube fitted to the socket.

[Herald1360]

Originally Posted by Tractorfan

When they finally pack up you can use the glass bowl for all sorts of things. Whisky glass, flower pot, jam jar, the list could go on

Sounds like you've been exposed to the rather neat French idea of supplying mustard in useful tumblers with a plastic lid on. I'm sipping a rather nice Scotch from one as I type

Getting somewhere close to topic..... the uplighter on top of my bedroom's wallcupboards is a 4ft fat tube fluorescent, housing probably 30 years old, but just a common or garden bi-pin.

[Brigham]

Originally Posted by Herald1360

Bayonet fitting tubes often just hung between a pair of dangling bayonet sockets so no problem fitting each one separately. More sophisticated lumieres would clip the tubes to the fitting, but still have flexible leads to the bayonet sockets to enable them to be fitted to the tube rather than the tube fitted to the socket.

The 5' types I have consist of a fixed socket at one end and a spring-loaded sliding one at the other. They aren't true bayonet holders, there being no 'nick' for the pins to twist into; the spring pressure holds the caps in contact.

[boxdoctor]

Originally Posted by raditechman

There was another similar fitting which used a filament lamp as the ballast. I cannot remember the wattage probably about 60watt bulb, not sure of the tube possibly a 65watt.

I remember these bulb-ballasted fittings, they were installed in a shop I worked for in the 'sixties. The bulb was at one end, and had an internal metallising on the lower half of the globe, so any light from the bulb was reflected up into the reflector above the bulb. Tony

[Zelandeth]

The idea of using an incandescent filament as a ballast is still used in blended mercury lamps today, though they are losing popularity nowadays as there are far more efficient types of lamp out there. They do however tend to be very long lived. There's some background information on them on this page of my website if you're interested.

With regards to the fitting arrangements for bayonet ended tubes, at least one end tended to have a free-hanging or at least long-leaded cap which allowed it to be fitted to the tube.

At work we don't have bayonet tubes with the building having gone up in the 60s - but do have a whole bunch of T12's in the office (including zillions of the short and stubby 20W ones). These are all held in place in a similar manner to what I imagine a number of bayonet ones would have been - with each tube held in place by two terry clips, and the lampholders just clicking into place on the lamp caps. Just wish the covers were as easy to fit as the tubes!

These ones seem to be fantastic from the perspective of behaving very erratically and swirling madly for the first few minutes of operation too when a new tube is first fitted - imagine that's more down to the control gear than the tubes themselves though.

[crusher19860138]

I work on the railway and we have both 2 foot and 4 foot tubes in the carriages with the strip running from one end cap to the other. We call the strip the 'p***er' strip, as we get a belt off the tube when touching the strip with the carriage lights on! The tubes are powered from 24 volt or 110 volt inverters (depending on the carriage type), made by Thorn.

[Tractorfan]

Quote by Herald1360 - Sounds like you've been exposed to the rather neat French idea of supplying mustard in useful tumblers with a plastic lid on. I'm sipping a rather nice Scotch from one as I type

Certainly have, although I don't like mustard or whiskey

I've got a 2ft 40watt tube that I've had for years, but never seen a fitting for it.
Strangely, 5ft tubes seem to be rare in France, although 4ft 36watt ones are very common.


Cheers, Pete

[Tazman1966]

Originally Posted by Tractorfan

...Strangely, 5ft tubes seem to be rare in France, although 4ft 36watt ones are very common...

Similarly, I've never seen anything larger than 5' in Cyprus. There are many very old fittings which seem to have been manufactured over there under the brand name "Cyfelco". My Nan's got a very old 4' 40W fitting in her house which I'll take a photo of next time we're over there.

[Welsh Anorak]

Hi
Silghtly OT, but I popped down to the factors earlier to get a new 8' tube for the workshop and was told they are now getting hard to obtain as they aren't energy efficient enough. Is this true or was he justifying the high price??
Glyn

[Tractorfan]

Hi,
Not heard that one before, but it wouldn't surprise me if it's true. A few modern supermarkets around here now seem to have thin (possibly T8) tubes that look very long and fragile .
I wonder if two 4ft tubes would work in series? I know that two 2 footers will work on a 40watt choke.
Cheers, Pete

[Framer Dave]

I was told the same as Glyn by a local wholesaler, however he did have the 8 foot T12 tubes I wanted. He said that they now seem only to be made by Sylvania. Mine cost £9.95 each.

[Hunts smoothing bomb]

This is true,

I am currently replacing the old 8' fittings with twin 5' jobs during the holidays at the school where I work as I can only get 100w 8' tubes now which are made by Sylvania, they would cost me £175 per box of 25, quite shocking really as the last box cost around £87!!! 125w simply don't exist anymore.

Cheers

[broadgage]

My interest is old lighting and related technology, not primarily radio equipment, so I will probably be most active in this section of the forum.

I would urge that anyone who has old flourescent lighting equipment, that they wish to keep in working order, should urgently obtain a good stock of replacement lamps.

Under EU energy saving rules, the import or manufacture of many older types of flourescent lamp is being prohibited.
Existing stocks may be sold or used without concern.

AFAIK the following types are, or soon will be banned.
All 8 foot tubes.
All common types of T12 tube (one and a half inch diameter)
All older type circular flourescent lamps.
All common types of halophosphate phospor lamps.

Older types of switch start fitting will usually accept a modern T8 lamp.
Transformer start or semi resonant start fittings wont normally start a modern T8 lamp, unless retrofitted with modern control gear.

Old type 5 foot fittings with 65 watt switch start gear should work a modern 58 watt lamp
Old 5 foot fittings with 80 watt switch start gear will light a modern 58 watt lamp, but badly over-run the lamp.
Old fittings with non switchstart gear wont normally work modern lamps.

Many retailers and wholesalers still have stocks, but when these are gone I doubt that more will be manufactured.

The restrictions on the sale of some incandescent lamps are fairly well known, but the situation re flourescents is perhaps less well known.

[broadgage]

Originally Posted by Tractorfan

Not heard that one before, but it wouldn't surprise me if it's true. A few modern supermarkets around here now seem to have thin (possibly T8) tubes that look very long and fragile
I wonder if two 4ft tubes would work in series? I know that two 2 footers will work on a 40watt choke.

No, two lamps each of 4 foot wont work in series from an 8 foot ballast.
8 foot lamps are indeed being withdrawn for energy efficiency reasons, it is not the length as such that is banned, but the older and less eficient style of lamp.
In theory it might be possible to make a T8 reduced wattage lamp and a matching electronic ballast. In practice I doubt that it will happen.
For everyday modern lighting in modern premises, I urge something more efficient.

However for those who wish to keep old fittings in use for a vintage look, it would be advisable to stock up on 8 foot tubes.
Some suppliers still have stock, but not perhaps for much longer.

[Denis G4DWC]

Thanks for the heads up on 8ft tubes becoming unavailable. I have quite a few of those fittings around the place. The one in the garage has always been difficult to start in cold weather so I replaced the starter with a Biased toggle switch which has a bit of string hanging down. Switch on lights, pull string till ends glow and release whereupon it usually strikes. Been that way for nearly 40 years! I'm surprised the old Toggle has survived.

Denis

[sentinel040]

We used to have a loco shed with 8 foot tubes and the blighters were right so and so's to get to stike on a winters night, if more than a couple came on you were doing well, good job I knew my way round 08's in the dark.....

Ian

[KeithsTV]

I had an 8ft tube in my loft which stopped working so I replaced it with a 6ft fitting and decided to try to fix the 8ft fitting and fit it in the garage. Thinking it was the tube I bought another tube but got exactly the same result - no light. There was a capacitor in series with tube which I replaced with one from a scrap fitting at work. This made some improvement but fitting the second capacitor in parallel with the first made the fitting work reliably and it proved that there was no fault with the original tube.

Any one want an 8ft tube? One careful owner.

Keith

[broadgage]

In many old, and newish, flourescent fittings the capacitor is wired accross the mains supply and plays no direct part in lamp operation, it simply improves the power factor.
However many 8 foot and some 6 foot circuits have the capacitor in series with the lamp, it then forms a part of the circuit and the lamp wont run without it.
Complete failure is generally obvious and replacement is easy.
What is less obvious is gradual loss of capacity, this reduces the lamp current, perhaps to the point where the lamp strikes on a warm day but not a cold day, or where one brand of lamp works but not another brand, or the lamp works on 240 volts but not on 230 volts etc.
Replacement capacitors are readily available, they are nothing special, any capacitor with an AC voltage rating at least equal to the original, and a similar capacitance will serve.
Care should be taken if connecting an old and a new capacitor in paralell, the total capacitance and therefore the lamp current may be greater than intended.

[KeithsTV]

I take your point but as the light is in the garage and only illuminates the work bench it isn't in regular use so I'm not that bothered by shortening the tubes life and I have a spare tube. I'm sure the cap I put in parallel was the same value as the original but I can't remember if I measured the values of the two caps as it was several years ago. If I ever have to take it down I'll check the cap value.

Keith

[broadgage]

Originally Posted by kalee20

Did the cathode need a heating supply for use on DC mains

No heater supply was needed, once lit the cathode remaind hot enough for continued operation.
The shorter flourescent tubes can be used from relatively low DC voltages.

As a teenager in the 1970s power cuts I worked 18 inch 15 watt flourescent lamps from a 72 volt DC supply, 2 foot 20 watt lamps worked in ideal conditions, but not with long cables or a low battery.
I used the original choke, a 4 pin thermal starter, and a resistance in series with the choke.
The lamp current was less than in mains operation and I dont remember many lamp failures.
I believe that the very first battery operated flourescent lantern used an HT dry battery to work the tube directly, not a transistorised inverter circuit and low voltage battery as used nowadays.
Burggess safari light I think.