Philips SPP 1000W Pulsed super high pressure mercury projector lamp

Super high pressure mercury lamps are compact highly loaded gas discharge lamps with a spectrum similar to daylight. They are today mainly limited to short arc UV sources for developping photo lacker on semiconductors and PCBs.
There is however another type that used to be more common. Mercury capilary lamps.
In difference to the short arc lamp with a bulged quartz arc tube and a short arc thes are very thin lamps with a much longer electrode difference. This long and thin lamps design stresses the quarz envelope more. The form is not ideal to withstand high pressures and often enough has a to small survace area to cool the quartz wall sufiently and so prevent catastrophic lamp destruction, even if forced air cooling is used. Therefor most capillary lamps need to be cooled with high velocity whater in order to prevent flash boiling of the same. Before beeing replaced by xenon short arc and metal halide lamps, capillary mercury lamps were used as projector lamps as well es some special industrial apllications.

Philips offered two lamps in this SPP series specially developped for cinema projection. These are small capilary mercury lamps opereted on pulsed DC with a frequency of 60-120Hz. This allows to omit shutters in movie projectors, while still making sure that the picture is only projected when the complete picture is in the lit window.

I tried to find out more about the circuit driving these lamps. However I was not able to find anything of value.
These lamp need to be precisely striked in their inteneded application in cinema projectors without shutters.
Philips specifies an ignition voltage of 1.2kV. Im am certain that the energy for the pulse is stored in a capcitor charged that is then discharge either thrue a transformer or directly thrue the lamp. However what interest me is how the lamp was striked. It has no auxillery stricking electrode like some Xenon flash lamps have. I suspect something like a thyrathron may be used but I am unsure. Id like to learn more about these lamps and how they are operated.

There have also been othe rappliactions likely in the developmment of photochemical materials. According to philips these lamps originally camed with an idividual reflector for every lamp. Obviously it is missing with this lamp. Howevr, I was also told by another collector who has seen a projectors with these lamps, that several of these lamps would be loaded in drum similar to the one found in a revolver. The lamps could then be rotated and changed during use, when the shutter was cold. On possibility may be that the lamp would be changed after ever flash, in order to ensure the lamps temeparture does not exceed the maximum ratings when air cooled.


This lamp come from ebay from a factory surpluce sale company. They said they came from a lab they closed down.


I belive that this is one a the few forced air cooled lamps.

Please note:
Philips does only states an ignition voltage at 1.2kV but a current of 2.1A. I belive that is the median current thrue the lamp during one pulse or possibly several pulses. Calculating a lamp voltage is difficult from that.
Philips also only states an lummen effiency of 55lm/W but not an overall light output. Again Light output is likely very different from an ideal square wave.
I still have something like half a dozen of those for trade if someone fancy one, drop me PM.