Thorn EMI Alpha 1

This lantern came from column 35454 on Station Rd, Mickleover, as part of a replacement scheme along the road - full documentation can be found here. It was, in fact, the last Alpha 1 along the road when it was removed on Wednesday, 23rd March 2005, almost three years after my first Alpha 1 was removed - funny how that happened! Although I already have an Alpha 1, I wanted this one as it has a slightly different shoe and is fitted with a NEMA socket - when most of Derby's Alpha 1s have the socket fitted at the top of the column. With it having the additional 'EMI' labelling, I believe that this may be newer than my first Alpha 1; probably, dating from the mid-1980s.

To see pictures of this lantern in-situ, please click here.

The Opticell on this Alpha 1 is the same (appearance-wise) as my first one is; however, the grub screws on the EMI example's shoe are set lower down and there are only two of them, whereas there are three on the other Alpha 1. The screws actually came undone without any trouble whatsoever - now, that's unusual!

The shoe on this Alpha 1 is also (marginally) narrower and is less curved than the older one is. The two pop rivets hold the internal top hooks (that the Opticell fastens onto) in place - in the older version, the hooks form part of the casting.

The underside of this lantern bears little difference to that of the older Alpha 1 - in fact, all that really seems to differ is the label inside the Opticell.

Aside from the addition of the EMI suffix, the other details on the label are unchanged.

The NEMA socket has no manufacturer's name on it, but it could be an old Fisher Karpark one, and was probably fitted in the Thorn factory.

Restoration of this lantern began on the 25th May 2005 and finished a day later. I started by giving the lantern a much needed cleaning. Both the shoe and the Opticell were cleaned without a problem, and then the shoe was repainted. A 1980s' SS4 photocell has also been fitted in place of the S90, as it is more in-keeping with the age of the lantern.

The lantern was mounted to an AC Ford AC872 wall bracket on Saturday, 13th August 2005.

It was powered up on Friday, 26th August, using a ballast and capacitor that had been salvaged from another column on Station Road, but of exactly the same type as had been fitted in the base of this lantern's column. Interestingly, the BICC-made capacitor was manufactured in November 1970, suggesting that the Alpha 1 scheme on Station Road dated from around 1971.

Lantern 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
235.6 0.6 119 141 49.9 0.81 114.50 24.50 27%

Abacus AM 202 | GEC Z8260




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