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Fluorescent Fitting. How Long Has This Been Going On?

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I was relamping some old high level 5 foot fluorescent fittings today. The Thorn Popular Pack type of old. They were fitted with Atlas tubes. So, I was wondering, what is the oldest working fluorescent fitting that you have come across with a heavy wound magnetic ballast and fluorescent starter unit?


Z.


  • 0
    I remember in the 80s, my headmaster changing the tubes in the ancient fittings in the 4th year classroom. He had some bayonet to bipin adaptors.


    The building was ex RAF from ww2, so the fittings with bayonet holders may well have been original. They were 5ft, not sure of wattage but probably 80... and absolutely enormous even by 1980s standards, they looked like aircraft carriers on chains!
  • 0
    Fluorescents are actually easier to start and run than most believe. We used to get criticised carrying them round power station sites during school visits. If you held them near vertical under the overhead substation connections, you could get them to light from where you were holding them to the top, like a Star Wars “light sabre”. The guides couldn’t explain to the kids why they lit. 


    Regards,


    Alan.
  • 0
    If ones shoes produce static electricity on certain types of floor covering, it can be entertaining to carry around a fluorescent tube. Hold one end with the pins touching the skin, and apply the other end of the lamp to anything earthed, a brief flicker of light results.

    Also the fur of a cat may gently stroked with a small fluorescent lamp, if the fur be sufficiently warm and dry then the lamp will flicker.
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    The guides couldn’t explain to the kids why they lit. 




    I suppose they could not explain why you need a larger gap between the high voltage  wires then LV ones either ?. (as it is the same reason)

    It is a bit worrying that no-one thought it necessary to fill in their knowledge gaps and find out.

    They also make quite good detectors of large RF fields as well - if you walk up to an HF  transmitter holding one and it lights in your hand, it is time to think about not getting that much closer.


  • 0
    I did some experiments with 2 and 4 foot tubes starting them with a filament lamp as ballast instead of a choke it worked really well starting was a bit slower and the tubes didn't run as brightly as with the proper choke  anything bigger than 4 foot just didn't want to know. If anyone wants to try it I found a 100 watt filament lamp is needed for a 20 watt tube measuring power consumption showed around 28 watts with the tube nicely warmed up.
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    For a single 2 foot, 20 watt tube, a good approximation of the correct tungsten lamp is a 196 volt, 100 watt lamp. These are still available.

    For a single 4 foot 40 watt tube the correct series tungsten lamp is about 150 volts, 75 watts or 160 volt, 80 watts. No longer readily available.

    Five foot, 65/80 watt tubes were not often operated on tungsten ballasts but can be used with a parallel pair of 150 volt, 75 watt tungsten lamps.


    Only the T12 argon filled lamps will start reliably on such circuits.


    The miniature 12 inch 8 watt tubes work fine in series with a tungsten ballast. 10 bulbs in series, each being 20 volt 3 watt works well. (old type Christmas lights)


    Mercury vapour lamps can also be run in series with tungsten ballast lamps. A pair of mercury vapour lamps and a single 240 volt filament lamp will work, all three in series from a 415 volt circuit. The efficiency is greater than with tungsten lamps only, and the colour rendering is better than with only mercury lamps.
  • 0
    It is a fun thing to open an old fluorescent starter unit, or new one if you can afford it, and remove the small glass bulb inside. Release the small glass bulb from its connections. Then in a darkened room, say a garage, throw the small glass bulb onto a concrete floor and watch the light produced briefly. WARNING this is an addictive hobby, a bit like popping bubble wrap bubbles. I believe that therapy classes are available for both addictions.


    Z.

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