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RLOD#19 (2020.05.25) 1970s PЭЛЗ ДКсЭл 1000-1 Manufactured during Soviet times, this 1-kW xenon short-arc lamp of Latvian origin features a remarkable design which was unique to PЭЛЗ, the local state owned lamp maker. This ДКсЭл 1000-1 has a 3-part bulb construction with highly unusual end seals which consist of a thin metal disk pressed against a heavy quartz termination by a mechanical assembly that includes conical steel washer springs and clamps. The malleability of the metal alloy used for the pressed disk ensures a gas-tight seal compatible with the high internal pressure typical of those lamps (i.e., several bars when cold to several tens of bars in operation). Interestingly, the heavy electrode assemblies are entirely supported by the end seals, which must be quite stronger mechanically that the usual graded-glass feedthrough normally employed in such lamps. PЭЛЗ developed this particular lamp design certainly as a result of crippling limitations in manufacturing skills and/or capabilities that often characterized small Soviet manufacturing operations. Typical of early xenon short-arc lamps, the ДКсЭл 1000-1 is intended for an operation in the vertical position with the cathode down. Keywords: Lamps

RLOD#19 (2020.05.25) 1970s PЭЛЗ ДКсЭл 1000-1


Manufactured during Soviet times, this 1-kW xenon short-arc lamp of Latvian origin features a remarkable design which was unique to PЭЛЗ, the local state owned lamp maker. This ДКсЭл 1000-1 has a 3-part bulb construction with highly unusual end seals which consist of a thin metal disk pressed against a heavy quartz termination by a mechanical assembly that includes conical steel washer springs and clamps. The malleability of the metal alloy used for the pressed disk ensures a gas-tight seal compatible with the high internal pressure typical of those lamps (i.e., several bars when cold to several tens of bars in operation). Interestingly, the heavy electrode assemblies are entirely supported by the end seals, which must be quite stronger mechanically that the usual graded-glass feedthrough normally employed in such lamps. PЭЛЗ developed this particular lamp design certainly as a result of crippling limitations in manufacturing skills and/or capabilities that often characterized small Soviet manufacturing operations. Typical of early xenon short-arc lamps, the ДКсЭл 1000-1 is intended for an operation in the vertical position with the cathode down.
2020-05-23_CDM86021V21O214K21EA21BT37.jpg 2020-05-25_RELZ_DKsEl-1000-1.jpg 2020-05-30_Philips_UHP_300W_1_3__.jpg 2020-05-26_Philips_DL50.jpg 2020-05-28_GEC_HPS21U_120W.jpg
Lamp/Fixture Information
Manufacturer:PЭЛЗ (RÈLZ)
Model Reference:ДКсЭл 1000-1 (DKsEl-1000-1)
Lamp
Lamp Type:Xenon short arc
Filament/Radiator Type:Highly loaded arc in xenon
Base:SFa28-7.4
Shape/Finish:Spherical clear
Service Life:1.6 kh @ 985 W
Burning Position:Vertical cathode down
Electrical
Wattage:650‒1050 W
Voltage:19.7‒22.3 Vdc
Current:33‒47 Adc
Optical
Lumen Output:20.4‒36.8 klm
Lumen Efficacy:31.4‒35.0 lm/W
Colour Temperature:6226‒6301 K
Colour Rendering Index:95 Ra8
Physical/Production
Dimensions:260L x 43Ø mm
Factory Location:Riga, Latvia, USSR
Fabrication Date:1970s
Application/Use:Movie projection
File information
Filename:2020-05-25_RELZ_DKsEl-1000-1.jpg
Album name:Max / Random lamp of the day
Keywords:Lamps
Filesize:443 KiB
Date added:17 Aug 2025
Dimensions:1200 x 800 pixels
Displayed:15 times
URL:https://trad-lighting.net/gallery/displayimage.php?pid=952
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Comment 1 to 6 of 6
Page: 1

Ria   [Sun 17 Aug 2025 at 14:56]
Interesting. I've always been rather cautious with regard to these things, they do have a bit of a reputation for going bang Mind Blown Laughing
Max   [Mon 18 Aug 2025 at 05:41]
Those lamps are relatively safe as long as they are treated with care, but personal protection is certainly required when they are taken out of their cover. It's the used ones, with an aged quartz bulb exposed to heat and UVs, that are most at risk of bursting. I have only a couple of those and, luckily, the ДКсЭл 1000-1 is not one of them (imagine, Soviet quality and aged bulb... what could possibly go wrong?).
Tuopeek   [Tue 19 Aug 2025 at 10:22]
Interesting, not seen a rounded end on an anode in these lamps before.
Max   [Tue 19 Aug 2025 at 11:38]
You're right, that's not a usual xenon lamp anode design indeed. But again, there are not many usual design features in that lamp. Maybe they went for this anode profile in order to maximize service life via a lower electrode surface temperature than the usual tronconic profile. But that must certainly come at the cost of arc stability as the arc is more subject to flutter due to the smaller resulting changes in arc impedance in off-axis paths.
Tuopeek   [Tue 19 Aug 2025 at 20:37]
Arc wander did cross my mind too then I saw the shape. Perhaps the low impedance and high current stabilises it to some extent.
Max   [Thu 21 Aug 2025 at 21:16]
It's difficult to say. Overall, it depends also on other factors such as the cathodic arc jet and its changes due to cathode ageing, and on the strength and stability of the convection flow in the bulb.

Comment 1 to 6 of 6
Page: 1