Lantern acquired in July 2010.
Thanks to Pete Greenall for donating this lantern to the collection. Being designed for fluorescent lamps, the HW-727 is a rare lantern throughout the UK; this particular example was removed from private land in Glasgow by contractors. I know of one example in Derbyshire, and again, this is privately owned but has not undergone any maintenance for many years.
The HW-727 is recognisable by its sleek appearance and shallow bowl. When the lantern was removed, a short length of the bracket remained fitted - this was duly removed from the lantern's spigot.
From above, the lantern resembles an elongated HW-918.
The bowl has become slightly cloudy through age, although the lamps are still visible inside. The bowl has no refractors in which to diffuse the output from the lamps moulded into the plastic.
The lampholders are spring-loaded. This allows the lamps to be held in place during operation, and then easily removed for maintenance. The two rear lampholders (seen on the left here) are discoloured from being partially submerged in rusty water, owing to water gathering in the bowl as a result of the tilt on the lantern when installed.
The hinged sheet aluminium gear tray doubles up as a reflector. Despite this lantern's age, all of the fixings are free from corrosion, and all appear to be turning without a problem.
Unfastening the gear tray reveals the enormous ELECO SMQFH/2240/TF high power factor ballast. This unit combines the functions of a ballast, starters and a capacitor. The bracket would be secured using the clamp on the left. Loosening this did not, however, immediately free the pipe, owing to a build-up of corrosion around the spigot. A few gentle taps from a hammer soon 'persuaded' the remains of the bracket to part from the lantern!
The operating voltage of the ballast is stamped on after manufacture - '240' can still just about be seen here.
A wiring diagram is also provided on the ballast - this may prove useful in the future!
The lantern was attached to a wall bracket on Sunday, 27th May 2018. As things turned out, the wiring diagram was not needed - the only wire requiring replacement was the one linking the two lamps at the front of the lantern. Fitting to the lantern to the bracket was a rather different kettle of fish, however - this was probably the worst lantern ever for securing to a bracket - although designed for 34 mm diameter brackets as a maximum, the clamp that is supposed to hold the lantern in place is unable to be tightened sufficiently for it to be of any real use. In the end, I resulted to affixing the lantern to the bracket using hot-melt glue!
Initially, the lantern continued its ability to be highly annoying into its operation - the electrodes glowed but the lamps would not light fully. I assume that one of the lamp pins wasn't quite making contact with its lampholders, as the lantern worked perfectly after both lamps were removed and then re-inserted.
The bowl produces a slightly diffused effect, owing to clouding that has occurred to the Perspex over the years.
Lamp switch-on video:
Testing with my energy monitoring device revealed the following results; interestingly, the Power Factor was rather poor, although the true power suggested that the lamps were under-running:
|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|
Philips 'Mini Iridium' BGS 451 | Thorn Alpha 1
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