MAIH 2000 B High Wattage Metal Halide
MAI is the term used by former French lamp manufacturer 'Compagnie des Lampes' for its general purpose metal halide lamps.  Of this 2000W variety, two types were manufactured - the type 'A' having a short arc and being intended for use on a low voltage single phase supply.  This type 'B' was was intended for use across the terminals of a 3-phase electricity supply, and has a long arc which offers improved system efficacy and lamp life.

Mercury and metal halide arc tubes are generally filled with a buffer gas of high purity argon, in which the initial discharge is struck when the lamp is first energised.  Heat from this discharge causes the mercury to vaporise and increase the wattage in the arc tube, then bringing the metal halide vapours into action if present.  But with an arc so long as in this lamp, and no auxiliary electrode being present to help strike the discharge, a very high striking voltage would be required if no other measures were employed.

To get around this difficulty the arc tube also contains a small percentage of neon, which effectively lowers the striking voltage.  Pure neon cannot be used since its striking voltage is higher than for argon.  The use of neon is usually avoided in lamps having quartz arc tubes, because at their high operating temperature they become increasingly permeable to its small atoms.  In normal use the neon would diffuse out of the arc tube during lamp life until a point would be reached when the arc could no longer be struck.  This effect is countered by filling the outer envelope with a nitrogen-neon mixture to eliminate the neon concentration gradient through the arc tube wall.  Neon is not lost from the outer bulb, which is made of borosilicate glass and runs much cooler.
Manufacturer: Compagnie des Lampes
Lamp Power: 2000 Watts
Lamp Current: 8.6 Amps
Lamp Voltage: 240 Volts
Cap: E40s/89x82 nickel plated with porcelain insulator
Bulb Finish: Clear borosilicate
Bulb Type: TT-100
Overall Length: 448 mm
Light Centre Length: 265 mm
Electrodes: Thoriated tungsten
Inner / Outer Atmosphere: Ar,Ne | Hg (Na,In,Tl,Li)Ix Outer: Nitrogen-Neon
Luminous Flux: 180,000 lm (100 hrs)
Luminous Efficacy: 90 lm/W (100 hrs)
Colour Temperature & CRI: CCT: 5600-6000K CRI: Ra 90
Chromaticity Co-ordinates: CCx: CCy:
Burning Position: Horizontal
Rated Life: 6,000 hours (to 50% survival)
Warm Up / Re-strike Time: 8 minutes 15 minutes max.
Factory: Pont-a-Mousson, France
Date of Manufacture: April 1978
Original / Present Value:
 
References: 1) Compagnie des Lampes (French Mazda) Catalogue, 1982.