Thorn Beta Six / AEI Saxby

Lantern(s) acquired in April 2021.

These two lanterns were installed alongside the Leander Architecture building on Hallsteads Close, Dove Holes, Buxton, and were photographed previously as a Survivor from the Past article. The condition of their columns was becoming increasingly poor, especially after one was struck by a vehicle in 2020, and so, the building's landlord decided to remove them; this taking place on Saturday, 10th April 2021. Thanks to a previous request that I made for these, the lanterns (and their brackets) were saved for me, and I picked them up a few days later - thank you to Leander for agreeing to my request, and for holding onto them until I could pick them up! No other known examples of Beta 6 lanterns exist in Derbyshire - their twin 40 Watt 2 ft (600 mm) fluorescent lamp requirement never being a popular choice for street lighting in the area.

The first column, pictured in 2017, looking rather the worst for wear.

Even from the ground, the absence of lamps in this lantern was obvious.

The second column was in equally bad condition at the time.

The innards of this lantern appeared more intact, however.

The two lanterns, in as-received condition. The lantern without lamps turned out to be an empty shell, with the gear tray missing completely. This is the worse of the two lanterns - its acrylic bowl features a number of cracks. The aluminium brackets are, as would be expected, still in very good condition, and should clean up quite nicely. The lantern that retains its innards sees both lamps stacked vertically, with moulded prismatic refractor prisms on the sides of the bowl providing limited optical control.

The bowl design features no refractors beneath the lamps, although some faint patches of dirt and greenery exist in both of these examples.

Holes have been drilled at the backs of both bowls, in order to reduce the amount of water that is retained within the fittings.

As the old columns were cut, this view allows their hexagonal construction to be appreciated, along with the method employed to clamp the brackets to them.

The aluminium canopies of both lanterns are also clean and free of corrosion. Neither is drilled for photocell control, suggesting that the lights may have been switched remotely.

The front and rear ends of the lantern resemble those of the contemporary Beta 5.

With the two toggles released, the bowl hinges open and detaches easily. A self-adhesive sealing gasket is installed around the edge of the bowl, in an attempt to improve the sealing - this may be another modification made in service to try to reduce water ingress. Judging by the state of the gear tray / reflector, these efforts appear to have been rather fruitless.

Barely legible towards the back of the gear tray is the lantern's (very brittle) identity label, with both 'Beta Six' and 'Saxby' names included, though it is definitely a Thorn product, rather than AEI, as the Thorn logo is present on the left-hand side of the label (trust me; it is!). As well as the twin 40 Watt lamp type, there is also the inclusion that the lantern is made to B.S. 1788:1964 (Street Lighting Lanterns for use with Electric Lamps) - this being an amendment to the original BS 1788: 1951 (Street Lighting Lanterns - Electricity and Gas), but was, itself, superseded by BS 4533-103.1 (1981) (Luminaires - Performance Requirements - Specification for Light Distribution from Road-Lighting Lanterns).

Some of the phosphor coating has 'blown' off the lower lamp, although it may still work. Both lamps are made by Philips, and carry the date code '2A', which (for reasons that will become clear in a moment) represents January 1972.

The four lampholders are connected to flying leads, rather than two being fixed, as with the GEC Z8260; however, four fixed 'Terry' clips are installed instead, ensuring that the lamps are secure when in use. These have become rather stiff over time, and I had to be careful not to break the lamps when releasing them from the clips. The gear tray is held in place with two screws that keyhole into position. Of course, while the front screw turned with ease, the rear screw wasn't quite as accommodating, and I had to hammer the gear tray forward, in order to be able to remove it. As it is only a length of sheet steel with the edges bent over, a replacement could be fabricated, if necessary.

The lampholders carry British Lighting Industries (Thorn) branding, and naturally, proclaim that they are "made in Gt. Britain". Notice that both lampholders have earth wires attached, with these connected to a brass component that makes contact with the metallic end caps of the lamps. This assists with lamp starting in colder temperatures; indeed, both lamps appear to be of the MCF/A type, which features a thin strip of conductive material being applied along the length of the tube. For the most part, this coating has worn away, owing to the age of the lamps.

The gear comprises an AME 69082.4 Quickstart ballast (for running both lamps) and BICC Power Factor capacitor. As can be seen, the paint is flaking badly on this side of the gear tray, as well as on the ballast itself. I will attempt to see whether it works, however.

The ballast also carried British Lighting Industries branding.

The capacitor is dated to February 1972, meaning that the lamps fitted now are highly likely to be the very same lamps that were fitted almost fifty years previously!

Thorn Gamma 3 | ELECO HW-852




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