The lantern is recognisable by its white GRP front canopy and grey GRP rear section; a Zodion-made NEMA socket being fitted to the latter in this example.
The date wheel moulded into the NEMA socket suggests that it was manufactured in July 2010.
Only when the lantern is viewed from below do the changes between this and conventional Vectra lanterns become apparent. The lampholder is offset within the optic, in order to produce an asymmetrical light distribution, with the majority of the lamp flux being concentrated over the crossing point. This particular lantern has a left-hand distribution setting; the idea being that it would be positioned slightly in advance of the crossing (often, in the UK, this would be the post shared by a Belisha Beacon), though right-hand distribution settings were produced too. The usual figured optic is replaced with a more basic sheet aluminium reflector here - floodlights employ virtually the same type of sheeting as their means of reflection.
A label is placed over the lantern's post-top spigot entry position, and seems to indicate the need to remove a component but only replace it with another type when not mounting the lantern side-entry. This ensures that the lantern is completely horizontal; a requirement in areas when glare is required to be kept to a minimum.
The flat glass is surrounded by an aluminium support ring with a high lip around its top edge. This ensures that the lamp area is sealed to IP 66 with the cover in place. Should the need arise, the panel can be removed completely by pulling it away from its hinges.
The lantern's identification label is located behind the lampholder. By the time that it was made, WRTL's parent company, Industria Lighting BV, had merged with Indalux Lighting, forming the new 'Indal' company. This name was short-lived, however, as rival Dutch street lighting manufacturer Philips bought this company out very quickly, and were quick to cull many of the former Industria / Indal / WRTL lantern designs, especially the 'lamped' lantern ranges, owing to a sharp decrease in their popularity in favour of LED lighting technology. The lantern's part code, VRLX150GNLPHDYN, is a bit of a mouthful, but tells us that the lantern is the Vectra-X type, with a 150 Watt lamp, flat glass, NEMA socket and Philips 'Dynavision' electronic lamp control gear. Although the label states that a SON-T lamp is to be used, the Derbyshire examples always used ceramic metal halide (CDO-TT) lamps instead; these lamps being compatible with the SON gear.
The rear section is accessed separately to the front, with a stainless steel clip securing it to the lantern body. An option is to insert a self-tapping screw into the hole located on the flat section of the clip, as a precaution against the clip being opened maliciously. I hope that I am not alone in seeing an unhappy face in the top of the clip! The side-entry spigot is visible in this picture as well; a hinged panel allows either mounting method to be employed.
Opening this section reveals the internal wiring. The lantern is designed to make replacing gear components quick and easy - the NEMA socket and main supply cable connectors can be pulled apart, and the gear tray released by a sprung clip. As the Vectra lantern was designed to accommodate a ballast, ignitor and at least one capacitor, a lot of space is wasted in lanterns such as this one, where the work of three components is done by one.
With the gear tray removed, the supply cable compression gland is seen more easily.
The gear unit is capable of dimming the lamp, but only when an external dimming module is wired into it by means of the two blue connectors located to the right of the ballast. The module is not fitted here, and so the lamp would run at full output throughout the night.
The lantern was fitted to a wall bracket on Saturday, 12th May 2018.
A 150 Watt CDO-TT lamp was fitted, just to replicate the Derbyshire setup. The label explaining the need to replace a component within the bracket entry area was retained.
Once activated, the metal halide lamp warmed up rapidly.
When viewed from below, the light distribution seemed virtually unchanged to that of a lantern employing a symmetrical reflector.
The distribution was more obvious when the lantern was viewed from the front, with the offset beam pattern being apparent on the wall behind.
Lamp warm-up video:
Testing the lantern with my energy monitoring device revealed the following results; the electronic ballast providing an almost unity Power Factor.
| 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 |
| 243.2 | 0.68 | 165 | 165 | 49.9 | 0.99 | 163.72 | 13.72 | 9.15% |