|
Mazda ME/D Glass Type Short Arc Mercury |
The arc burns between electrodes of solid tungsten to provide a compact light source of extremely high brightness. This, the simplest design of ME lamp, has the arc tube housed within a simple hard glass outer bulb and the cap is the standard 5-pin plug, once the principal mains electricity socket in use in the UK. The arc tube is filled with an argon-neon mixture for easy ignition, and a third auxiliary starting electrode penetrates the side of the arc tube. The arc tube and its end seals to molybdenum ribbon is hand-made throughout. To produce a lamp like this having a very short light centre length, the conventional stem assembly of the outer bulb has been replaced with a flat glass flange with three tungsten lead wires sealed through it, to which the arc tube and its support frame is welded.
ME/D lamps were once very popular light sources for monochrome slide and film projectors, film printers, and a great many still live on today in technical instruments such as projection microscopes and profile projectors. In addition to this glass design, a lamp having a pre-focussed base was also sold, and a number of types in metal boxes having quartz or glass windows were also made. Today, for new applications they have been totally superseded by the double ended bare arc tube designs such as Osram's HBO range.
| Manufacturer: | Associated Electrical Industries Ltd. (Lamp 94-0051) | |
| Lamp Power: | 250 Watts | |
| Lamp Current: | 3.7 / 4.6 Amps | |
| Lamp Voltage: | 60 / 75 Volts | |
| Cap: | 5-amp plug | |
| Bulb Finish: | Clear | |
| Bulb Type: | T-50 | |
| Overall Length: | 141 ± 3 mm | |
| Light Centre Length: | 85 ± 1 mm | |
| Electrodes: | 3.75 ± 0.35 mm | |
| Atmosphere: | Solid Tungsten | |
| Initial Arc brightness: | 1.5% Neon in Argon | |
| Luminous Flux: | 20,000 stilbs | (1,300 MHCP) |
| Colour Temperature & CRI: | Not published | |
| Chromaticity Co-ordinates: | Not published | |
| Rated Life: | 500 hours | |
| Factory: | Leicester | England |
| Date of Manufacture: | September 1955 | |
| Original / Present Value: | £16 15s 0d (1969) | £166.75 (2001) |
