Compact Source Xenon Reflector EDR46 500W
Presented here is the first xenon short arc lamp with integral reflector, developed in 1965 by General Electric of USA. The fundamental principles of the short arc xenon lamp were established when John Aldington of British Siemens published his work in 1949. The idea was then picked up by German Osram, which refined the technology and introduced the first xenon short arc lamp in the early 1950s. Such lamps were the first to combine a short arc of extreme high brightness with high stability and high colour rendering, which made them ideally suited to projection apparatus in which they replaced the earlier bare carbon arcs.

Owing to the compact dimensions, precision alignment of the lamps within the optical systems of the projectors was of critical importance, and for many years this was a troublesome process. Another drawback was the high concentration of infrared in the xenon spectrum, which produced a great deal of heat in the beam. There were additional challenges relating to ozone generation from the shortwave UV-C emission, oxidation of the molybdenum foil seals of the arc tube, along with a substantial explosion hazard. All of these drawbacks were solved with the development of this GE CSX-R lamp, by pre-focussing the arc tube in a pressed glass reflector equipped with a dirchroic cold mirror, sealed under inert atmosphere, and having a UV-blocking glass outer jacket.

Unfortunately this design was limited to relatively low powers, whereas most applications called for xenon lamps above 1000W. As such this lamp found mainly specialised military applications, but it was also applied in the first of the GE Talaria digital video projectors of the early 1980s.
Manufacturer: General Electric USA Model 7380833GP14
Lamp Power: 500 Watts
Lamp Current: 27 Amps
Lamp Voltage: 18.5 Volts 20 kV ignition
Cap Type: AWG 12 stranded wires
Bulb Type: EDR-146 EDR-46 in eighths/inch
Bulb Finish: Ellipsoidal Borosilicate Dichroic Reflector
Electrodes: Solid Tungsten (thoriated) Zr getter on anode
Arc Length: 2.3 mm
Atmosphere: Xenon 8/30 bar cold/hot
Luminous Flux:
Luminous Efficacy:
Colour Temperature & CRI: 5800K Ra 100
Chromaticity Co-ordinates: CCx: CCy:
Rated Lifetime: 1500 hours to 75% flux
Warm-up & Re-strike Time: Instant Instant
Burning Position: Cathode Down ± 90°
Overall Length: 133.4 mm 51/4 inches
Light Centre Length: 42.9 mm 111/16 inches
Factory: NELA Park, Cleveland OH U.S.A.
Date of Manufacture: Approx. 1970 Date Code: 2028
Original Value:
 
References: 1) GE Brochure - Discharge Lamps for Special Applications, 1968 USA, p.27
2) GE Datasheet - 500W Xenon Compact Source DC Arc Lamp with Ellipsoidal Cold-Mirror Reflector Bulb, c.1965 USA
3) New Light Sources, Journal of the Society of Motion Picture & Television Engineers V.75, May 1966 pp.448-449