GEC 'Brookvale' Z5530

Lantern acquired in January 2008.

Thanks to Davy Warren for this lantern, which came from the village of Sparkwell in Devon, and was removed in September 2007, in order to make way for an Urbis Sapphire 1 running a 45 W CPO-TW lamp. No lanterns of this type are ever known to have existed on Derbyshire's streets, and so I was pleased to acquire a lantern that was unknown to this County.

A small section of the outreach bracket, along with the GEC top-entry finial, were still attached upon acquisition. Both these, and the lantern itself, are painted the light green colour that was applied to Devon's street lighting equipment in the past. Helpfully, 'Street Side' is cast into the 'front' of the aluminium canopy, as a way of ensuring that the lantern is orientated correctly in relation to the carriageway; the prismatic glass refractor bowl being engineered to cast the majority of the lantern's luminous flux down and to the sides.

     

The lantern wasn't quite aligned perpendicular to the bracket, however.

 

The underside of the bowl demonstrates the different types of refractors employed to maximise the lamp's output. Notice that a slot in the bowl retention ring prevents it from being fitted the wrong way around. Opening the bowl reveals the spun aluminium reflector above the 80 W MBF lamp.

     

The number '61' appears on the bowl's lip; this represents the year that the bowl was made; making the lantern approximately 47 years old upon acquisition.

 

A simple focusing mechanism is attached to the rear of the reflector; this can be adjusted by loosening a screw on the side and allows tungsten filament lamps from 60 W - 200 W and MBF lamps from 80 - 125 W to be focused correctly for accurate beam distribution. Such is the age of this lantern that it may have been designed to run the original 'pear-shaped' mercury lamps, instead of the later elliptical types. The supply cable terminates directly into the three-pin bayonet lampholder, and is rather charred from years of being in close proximity to the hot lamp. The focusing mechanism includes a detail stating that it must be used in conjunction with the Z6600/2 refractor bowl, which I assume this lantern's bowl is.

 
 

Over ten years after the lantern entered the Collection, restoration commenced in May 2018. The first task was to separate the lantern from the remains of the bracket. This was achieved by heating the joint between the two with a blowtorch and then striking the cut end of the bracket pipe with a hammer (with the lantern secured) until it began to unscrew. Typically, the coupler linking the bracket to the lantern remained fixed in the latter, and I pondered over whether to leave it fitted and simply screw the lantern into a replacement bracket, but because I like a challenge, I set about removing the coupler. This involved cutting slots along the length of the coupler using a hacksaw slotted through the top-entry hole, and then crushing the coupler down using a pair of mole grips until the friction was sufficient that the (now very battered) coupler would unscrew from the lantern.

 

As can be seen, the blowtorch had a detrimental effect on the paint finish, but this will be addressed at the next part of the lantern's restoration.

 
 

The 'next part of the lantern's restoration' saw the canopy sent away for bead blasting and repainting into the distinctive Devon 'mint green' colour. When it returned on Friday, 6th July 2018, I was amazed at the accuracy of the colour-matching tool that had been used; this ensured that the replacement colour was the same as the original.

 

The inside of the canopy was painted in light silver.

 

Meanwhile, the other components were treated to a warm, soapy wash in my "lantern cleaning machine", or a "dishwasher", as it is known outside of street lighting circles.

 

The lantern was then reassembled, and subsequently, fitted to a wall bracket on Friday, 6th July 2018. The bracket featured a 1′′ BSP right-angled bend fitted with a ′′ BSP reducer, and finally, a male-male coupler. New gaskets for the bowl support ring and bowl itself were applied, and because the wire used in holding the bowl glass in place was beyond repair, the bowl is now glued to the ring.

     

Naturally, its alignment was far more accurate on this bracket than it had been on the previous outreach!

 

The new 80 W MBF lamp warmed up to full brightness within a few minutes, meaning that the bowl's prismatic refractors were put to use again for the first time in over a decade.

     

Lamp warm-up video:

Testing with my energy monitoring device revealed the following results:

Test Voltage (V) Current being drawn at full power (A) Measured wattage (W) Apparent Power (VA) Frequency (Hz) Power Factor True Power (W) Difference to rated wattage Percentage Difference
247.8 0.48 106 119 49.9 0.89 105.86 25.86 32.33%

Thorn EMI Gamma 6 Traditional | Simplex Aries


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