WRTL 'Arc 90' 2695
Lantern acquired in March 2017.
This lantern was removed from column 8218 on the A516 dual carriageway in Mickleover; the double-arm column being removed from service on Friday, 17th March 2017 as part of road realignments that would see the construction of a new roundabout providing access to a new housing development on the opposite side of the A516; the same scheme that saw the acquisition of five other lanterns for the Collection. This lantern, and another Arc 90, were fitted to the existing column in the mid-2000s; the original lanterns (highly likely to have been Thorn Pilote T2s of equivalent wattage) presumably being found to be defective and needing renewal. Along with the smaller Arc 80 lantern, the Industria / WRTL / Indal / Philips Arc lantern is a common sight in Derbyshire; its popularity being attributable to the variety of lamps and mounting heights that it could accommodate. This larger version of the Arc was intended for main road use, with the 150 W type being the commonest variant in this area - the 250 W type being somewhat more uncommon, and 400 W being virtually non-existent.
These first couple of pictures, taken in January 2005, show the double-arm column shortly after the two Arcs were fitted. The right-hand lantern is the one that entered the collection just over twelve years later.
The double-arm column that supported this lantern, on the 20th January 2017 - a few days after the westbound carriageway was closed to non-construction traffic. By then, the road surface had been dug up and a contra-flow was in place on the eastbound carriageway.
The lantern closest to the photographer in this view is the one that entered the collection.
Just shy of two months later, the scene had changed somewhat - by then, the westbound carriageway had reopened (with the contra-flow swapped to this side as well), and the eastbound carriageway closed. This picture was taken on a rainy Saturday, 18th March 2017; a day after the double-arm columns had been taken down. The lantern can be seen in the approximate centre of the image, in lane two of this carriageway. A public footpath exists along the left-hand side, behind the orange safety barriers. Although this picture was taken at the weekend, when no work was taking place, dual carriageways should always be treated as 'live', and appropriate Personal Protective Equipment should be worn, as I was wearing.
Unlike the smaller Arc 80, which can have a polycarbonate bowl in the outward-facing section in its optic, as well as curved and flat glass options, the 90 is only available with the two glass options - although the polycarbonate has the advantage of being more resilient, it tends to scorch and discolour when higher-wattage lamps are employed. The lantern exhibits a slight 'battle scar' along this side, from where it was dragged along the carriageway after its column was brought to the ground.
Whilst my 70 W Arc saw relatively little outdoor use, this lantern was in service for over a decade, with the result that the slight glittery paint finish applied to the die-cast lantern body is more matte with this example, owing to it being bleached by the sun.
The curved glass bowl also exhibits slight internal clouding. Assuming that the optic can be taken apart (despite its sealed nature), this should wipe off. When this lantern was produced, WRTL's parent company was the Dutch 'Industria' group; hence, the appearance of this company's logo on the underside of the lantern. Following a merger with Indalux Lighting, the company became 'Indal', before a buyout by rivals Philips saw the WRTL, Industria and Indal brands disappear.
A Royce Thompson Oasis 1000 photocell dating from August 2004 and rated at 55 Lux is fitted in the lantern's NEMA socket. This is likely to be original to when the lantern was installed, but has probably never seen a full dusk-night-dawn-day cycle, owing to the bypass lighting being group-controlled from a master photocell, which would deactivate the Oasis once ambient light levels were sufficient for the street lighting to be switched off. The Oasis' printed circuit board is also slightly faded; again, because of sunlight.
Removing the photocell reveals that the NEMA socket was made by SELC. Notice that a small ring of the lantern's 'original' shiny finish exists around the NEMA socket; this is where the presence of the cell prevented this part of the canopy from being bleached.
A simple stainless steel catch located at the front of the lantern secures the canopy to the rest of the lantern chassis. A slight indentation is provided, in order to allow anyone working on the lantern to place their fingers beneath the clip, and pull it upwards; releasing the canopy.
With the canopy opened, the logical layout of the lantern's components can be seen. An elliptical polished aluminium reflector surrounds the lamp, whilst the lamp control gear and wiring is situated towards the rear of the lantern. The streaky lines that are visible on the reflector is condensation - when the lantern was lowered to the ground after its column was cut down, the canopy opened (probably from the force of being dropped on the hard ground) and the rain of the 18th March was able to enter the usually-sealed lantern interior.
This lantern is of the 'DIP' (Double Ingress Protection) variety - as well as the general interior being sealed to IP66 (by means of the red foam gasket that passes around the inside of the canopy), the optic itself is also sealed to this degree of protection. A slightly different option is for the lantern to have 'Single Ingress Protection' only, where the reflector attaches to the canopy (by means of the screw hole visible here) and is moved out of the way when the canopy is lifted.
Once the canopy is opened, a sprung metal strip ensures that it remains upright, and can only be closed again by the operative pulling on the strip. With the canopy opened, the supply to the lantern is isolated, thanks to the plug and socket arrangement that links the main terminal block with the NEMA socket, and from thereon to the control gear components. This ensures that failed lamps and components can be replaced without the concern that they may still be live. A compression gland provides a sealed passage for the supply cable to enter the lantern, though in the case of this example, the nut that activates the compression mechanism is missing - I suspect that this was removed during the lantern's installation, as the 2.5 mm2 twin-and-earth cable employed would be too wide to pass through the nut easily, and so this part was removed and discarded.
The lantern's tilt angle can be adjusted by loosening an Allen screw and adjusting the plate beneath it to the desired angle, using the arrow-shaped indicator as a guide. Interestingly, despite the lantern being configured for side-entry operation, the tilt is set to the 5 degree position if the lantern were installed post-top; the positions differing depending on the configuration. Incidentally, switching the configuration from one to the other involves removing this screw, which releases the spigot entry device, and allows it to be re-inserted the other way around.
Two 5 mm grub screws secure the lantern to its bracket or post. Arc lanterns destined for the UK market are supplied with a thick cylinder, which allows spigots of diameters narrower than the 60 mm size that is common in Europe to be utilised without the grub screws being too short and not gripping the bracket correctly, if at all. If the lantern is to be used in the post-top configuration, this adaptor is removed (by taking out both grub screws) as the spigot entry is wide enough to accommodate 76 mm diameter posts.
The identification label is located immediately below the compression gland, with 'AMR150CGN' being the catalogue number:
A = Arc
MR = Main Road version
150 = Wattage
CG = Curved Glass
N = NEMA Socket
Oddly, the label makes reference to 'GEC' after listing the lamp type - I am not sure whether this means the General Electricity Company, as their lighting division was sold off many years before the Arc entered production; indeed, some of the GEC lantern range was produced by Siemens before passing to Whitecroft Lighting, which later became WRTL - Whitecroft Road and Tunnel Lighting. The other label present in this area features the code '170903', which could be represent the date that the lantern was made - the 17th September 2003. If this is correct, this must be a relatively 'early' Arc lantern, as it was about 2002/3 that the lantern was launched.
A two-core flexible cable (with an unusual red sheath) connects the lamp to its control gear. This finishes at a terminal block that can be disconnected, in order to facilitate lamp changes. With the optic being sealed, the lampholder is attached to a plastic bung that also accommodates the lamp focusing mechanism, and prevents moisture and dirt from entering the optic area. The stopper is seen here in the 'C', or closed, position; it is rotated anti-clockwise to the 'O' (Open) marker and pulled outwards.
The combined stopper, focus mechanism, lampholder and lamp itself makes for quite a long assembly. It is for this reason that the cable to the lampholder can be disconnected - if it couldn't, the cable would be strained quite badly during removal.
The lampholder is slightly cranked in relation to the position of the stopper; this ensures correct focusing of the lamp within the optic. The Philips-made SON lamp carries the date code of '0L', which represents November 2010. A hand-written date on the lamp cap suggests that the lamp was fitted in April 2011; probably as part of a bulk lamp changing session; given the expense involved in repairing street lighting that is located within the central reservation of a multi-lane carriageway.
Four positions for altering the lamp's vertical focus position exist (1-4); the default is 1. In order to change this setting, the lampholder must be unscrewed from its fixing, and then reattached at the alternative position.
Five positions are available for lateral focusing (A-E). Here, position 'C' is the default; this is altered by loosening the screws situated on both sides of the stopper and then moving the plate left or right. The plate containing the focal options can, itself, be adjusted, though this is only necessary if the lampholder itself is to be changed for a different type - different-sized lampholders will cause the lighting centre to differ.
A "lamp's-eye-view" of the optic; the marks visible on the glass are where the lamp has rubbed away whatever has caused the slight clouding on the surface over time.
The lamp control gear components all attach to a plastic gear tray (meaning that the lantern doesn't require an earth, though a terminal is provided for continuity purposes); this clips into place and is removed easily - the incoming supply cables also terminating in a connector that can be unplugged. The ballast and ignitor are made by Parmar, whilst the capacitor is an Italfarad product. All carry 2003 as a year of manufacture as well, with the ignitor having the 14th July stamped on its casing. A number of unused fixing holes exist on the tray, in order to accommodate different components, depending on the lamp type and wattage employed.
With the gear tray removed, the unpainted aluminium chassis is visible.
The following photographs demonstrate the size difference between the small and large Arc lanterns - the small lantern measures (L) 670 mm [2 ft 2.4 in] × (W) 325 mm [1 ft 0.8 in] × (D) 275 mm [10.8 in], including the bowl. The large lantern measures 775 mm [2 ft 6.5 in] × 380 mm [1 ft 3 in] × 250 mm [9.8 in], including the curved glass, but excluding the photocell.
The smaller optic necessitates the need for the lampholder to be more recessed into the end section, though both lanterns are set to the same focal position - 1C.
Following a straightforward cleaning of the lantern (including removal of the optic for washing, and its subsequent reinstatement within the lantern), the Arc was fitted to a wall bracket on Thursday, 17th May 2018.
The familiar golden glow of a healthy SON lamp appeared quickly, once the lantern was switched on.
Lamp warm-up video:
Testing the lantern 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 (W)||Percentage Difference|
WRTL Arc Lanterns in the Collection
|Arc 80 (70 W)||Arc 80 (150 W)||Arc 90 (150 W)|
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