Philips MI55 GO

Lantern acquired in March 2008.

This variant of the familiar MI50 SOX lantern came from Becket Well Lane in Derby City Centre, adjacent the former Debenhams building, and was replaced with an WRTL Arc running a 70 Watt White Lux lamp - the idea being to match the metal halide lighting used on nearby Victoria Street. The MI55 is uncommon as a street light in the Derby City area, although privately-owned examples can be seen in Kombipack form (the SNK70) attached to buildings for security lighting purposes.

 If you position your mouse cursor over the highlighted photographs, the image will change for the equivalent one showing the Philips MI50 in my collection - in this way, both lanterns can be compared, as Philips launched both versions in 1981.

The canopies of the MI50 and MI55 are identical in appearance, whereas the bowls differ due to a) the MI50's bowl being a vacuum-formed reproduction, and b) the MI55's bowl being dirty and discoloured from being on a City Centre street for just over eighteen years - both the NEMA socket and capacitor are dated to August 1989. The P5 cell fitted to the MI55 is original and still works.

The aluminium finish is quite clean on both lanterns.

Even though the two bowls are quite different, the refractor panel positions remain the same for both.

The reflectors/gear trays on both lanterns differ slightly - the capacitor is visible on the MI50 whereas it isn't on the MI55. What cannot be seen here is that there is an elliptical indentation shaped into the MI55's gear tray to prevent the lamp from being pressed up against the metal.

With the MI55 being designed for internal-ignitor lamps (Philips only offering this type for 50 Watt and 70 Watt lamps at the time), the only gear fitted is a rather worn-looking ballast and capacitor, whereas an ignitor can be seen on the MI50's gear tray. The elliptical indentation mentioned above can be seen here.

The MI55 has a much smaller terminal block than that of the MI50 - again, this will be down to the difference in components on the two models. The brown object to the right of the NEMA socket is part of the plastic casing from the ballast...did I mention that it was a little worn?

Fortunately a replacement bowl had been obtained, and so this was fitted in place of the discoloured one. Notice how the refractor panels (designed for a SOX lamp) don't really 'work' with an elliptical SON!

The underside refractors are slightly more effective at distorting the lamp.

I replaced the life-expired gear on Saturday, 21st June 2008. Even when the ballast was being removed, parts of the casing continued to break off!

The lantern was then fitted to an AC Ford AC872 bracket. I decided not to repaint the gear tray/reflector due to the fragility of the internal label.

As the lantern is really just a converted SOX design, the optical performance is somewhat limited. The area on the bowl immediately surrounding the lamp also gets very hot whilst in use.

Lantern warm-up video:

These photographs show the column that used to support this lantern.

By April 2020, the Arc had lost its White-Lux lamp but gained a SON-T lamp instead!

By 2021, the building to the right of the column, which housed a church, shops, and Ranby's (later, Debenhams) department store, had been demolished, and the whole area was undergoing redevelopment. In all likelihood, this column will be removed in due course.

WRTL MRL 6 | GEC Z9538

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