Obsolete fluorescent light fittings

[cmjones01]

Originally Posted by Brian R Pateman

Unfortunately your Dad was wrong.
The fluorescent lights on LU are powered from good old fashioned AC mains. I have been responsible for the installation of many of them.

OK, I'm entirely prepared to believe that It was a good theory though. Actually, the specific one I can remember in my mind's eye (strange how odd memories hang on) was in or around a lift and in a very unrefurbished-looking station, which might have been an unusual case, I guess.

[Tazman1966]

I have noticed on the underground (in the stations that is) that when the fluorescent tube wears out, the fittings that they use cause the tube to continue to be alight but with a 50Hz flicker and darker towards the worn out end. I'll attempt to take a photo next time I get the chance.

[Hunts smoothing bomb]

Hi Tas,

These tubes, are they the fatter T12 size as opposed to the narrower T8 type? In my experience the T12 types often fail buy going like this or just a dull purple colour.

Cheers

[Tazman1966]

Hi Lee.

They are the T12 size and are various lengths. 2' 20W, 4' 40W and 5' 65/80W. They are being slowly but steadily phased out though by new fittings with T8 skinny tubes

Originally Posted by kalee20

I can't see that somehow - fluorescent lamps need AC to work. If you use on DC, then the tube would probably be unevenly illuminated; also, the cathode would need to be permanently fed with some sort of heating supply (while the anode electrode would be hot due to electron bombardment with no gain). On AC the heat generated in an end electrode in 'anode' mode is made use of during the next half cycle when it's in 'cathode' mode.

They were (are?) used on DC, the on off switch had a reversing action so each time you turned it on the polarity changed. Used quite a lot on ships.

[chipp1968]

Yes thats It in McMurdos picture ..Horrible I think it broke the light fitting in the end .Im sure it was in use for 10 years at least when it was replaced by a normal bulb.I think it was still working though may have been slow to work.
That reminds me in the garden shed at Mums the F Tube there must be pretty ancient .Certainly 30 years ago it was old then and used to flick flick with quite a noise then come on ,sometimes had to bang it ! Have to bang it quite a few times now !

[dseymo1]

I guess I'm not the only one with an old sluggish fitting in the shed which requires manual starting - i.e. flick the switch a few times until the tube strikes
Yes, I know it will eventually burn the switch contacts, but that's second-hand too, and there are plenty more where it came from

[julie_m]

When I was at school, we had a real problem with people stealing the starters from the light fittings.

In the end, a system was imposed: one starter per classroom would be kept in the teacher's drawer! Somebody would be chosen to go around at the beginning of each day, climbing on desks (no health and safety in those days) and inserting the starter in each light fitting in turn to get them to come to life.

In a similar vein, a friend once had a fluorescent fitting in his bathroom where the starter had failed short-circuit. Switching the light on entailed twisting the starter back and forth. What's more, since neither he nor his landlord could agree on who was responsible for fixing it, it stayed like that until he moved out.

[kalee20]

I replaced the starter of an old lamp fitting once with an ordinary bell push. Worked fine.

[m0cemdave]

Attached pic is of my favourite bit of fluoro gear, an Atlas thyratron houselight dimmer that I salvaged from a theatre albeit without the dedicated fittings to run from it. These have separate heater transformers run at full voltage whenever the tubes are lit. The dimmer handles five circuits each of 5A, under pushbutton control. I have some spare thyratrons too, one day I will either get some of the original fittings or modify some ordinary ones so I can get it running

That's exactly the same as the rack of house light dimmers in the main hall at my old University in the early 70's. The tilting mercury switches are very distinctive too.
The lamps were long Cold Cathode tubes.

[hotbulb]

Where I used to work we still had quite a few of the 5 foot bayonet cap type fluoro fittings in use when I left in 1988. The tubes were still available for replacement purposes then as far as I recall.


In my present building we have high frequency lighting with electronic ballasts. True, they may be more efficient but the ballast units definitely have a limited lifespan and I replace quite a few each year. Dissection of the old ones usually reveals exploded capacitors and/or power transistors.
There's a lot to be said for some copper wire and a stack of laminations in the reliability stakes....

[Courtney Louise]

I actually tried to buy an old tube the other day for my 1951 jukebox, it was 33" 25w and t12 in size, best I could get was a t8 which is too thin :-(

[julie_m]

My jukebox requires 660mm. 19 watt fluorescent tubes, which I couldn't get hold of. Apparently, neither could its previous owner; who had bodged in a couple of 300mm. 60W filament striplights -- one of which was right above the magazine, in the absolute perfect position to warp the records.

I added some spacers to reposition the lampholders, so as to get 600mm. tubes to fit. Although these are rated 18W and so being slightly over-run, they seem to work.

I really must treat the amplifier to some new capacitors, though .....

[matthewhouse]

Originally Posted by Jarl Ayari

...best I could get was a t8 which is too thin :-(

As far as I am aware, only 5' and 8' tubes are available in T12 now, according to the local wholesaler.

[Tractorfan]

Hi,
Before I left the UK I used to do voluntary work at some local aircraft hangars undergoing restoration. One of the hangars was lit with lots of 4 x 8ft fittings. They were very heavy with two sets of pitch filled starterless gear, one unit for two tubes. They were installed in the early sixties and used a non-standard end cap and sockets. The cap had a bakelite insert that was designed to engage positively into a springloaded socket at one end so that the tube could be fitted from the non-springloaded end. The tubes were of Canadian origin (possibly Sylvania, though I'm not sure), although I can't recall who made the fittings.
I was kept busy trying to make up good fittings out of the remains of failed gear and what few tubes that still worked The handy part was that they were easy to take down as they were plugged in with 13amp type plugs with a round earth pin and hooked onto the power trunking system.
Cheers de Pete

[arjoll]

Some quite interesting stuff here! Unfortunately I've 'arrived' a little late.

We had four oldish - probably 70's - fittings in our first house, two doubles in the garage, a single in the covered patio area and a single in a storage/gamesroom area. Just after buying the place in 1995 I had an electrician client inspect the place - other than the rubber covered cable and steel conduit around the place he flagged the fluros as possibly containing PCBs and needing replaced. Of course we never actually got around to doing anything! The next over was an electrician friend of ours, he replaced pretty much everything there so I guess they went as well!

Originally Posted by Zelandeth

Below is a picture of one from 1983.

We have a number of those at the local Ernst & Young office when I worked there as a graduate! They were in recessed downlights, mid 90's era. Most of the lighting was linear fluros but there were some of these in client areas. They were probably installed when the building was remodelled around 1990.

Originally Posted by ajs_derby

In the end, a system was imposed: one starter per classroom would be kept in the teacher's drawer! Somebody would be chosen to go around at the beginning of each day, climbing on desks (no health and safety in those days) and inserting the starter in each light fitting in turn to get them to come to life.

In '83-'84 at intermediate we had a similar system. All the fittings had starters, but usually half of them were stuffed - so every morning someone had the job of climbing up on desks and wiggling the starter on any light that was flashing!

[toshiba tony]

does anyone remember the 4 pin starters, ive a few in the loft somewhere

[kalee20]

Yes I do, but I never knew what the 4 pins were for. In the one I stripped apart (age 8 or so), two of the pins were linked, and the other two went to a little glass thing, which was rather blackened inside.

So - put me out of my misery - what were the extra two pins for? Glow switch starters are so simple and cheap.

[Tractorfan]

Hi,
Before the advent of glow starters the old ones had a pair of bi-metallic contacts and a little heating element. This element was connected between the pins that are now linked. Not sure of the exact circuit but I think it was in series between the choke & the tube end heaters. I seem to recall that someone even made an electronic solid state starter in four pin format.
While rummaging around the cellar I uncovered a 15watt, 18inch long T12 (1.5" dia) tube. I guess these are rare now? I've also got a couple of 6watt T8 tubes that don't seem to be a common type.
Cheers de Pete

[Hunts smoothing bomb]

Wow! I have never seen a 15 watt T12! a 20 & 40 watt yes, they are also bout 18" long.
I have never seen a 6 watt T8 either, I have 18 watt T8 and 6 watt T5 in stock at work. Do you have any pics?

Cheers