I've got a Ripley LongLife cell that rattles, it a small part of the board inside broke off, nothing important, just a little annoying! If I hold the cell above my head and look through the window and give it a bit of a shake, the broken piece falls down onto the window.

If it really bothers you, you could possibly attempt to remove the top of the cell, though that may just stuff up the whole thing. Not something that I've ever tried.

In practice, I'd say medium power transformer will have a longer thermal time constant than typical HID lamp run up time, so you will be ok choosing the transformer by warm lamp current. Okay for a controlled experiment when you monitor the circuit constantly. For normal unattended application better dial in some safety factor, and it is a wise practice to choose somewhat oversized transformers even for constant loads.

Other thing to consider, overloaded transformer will have slightly higher output voltage drop than expected at nominal power.

I have a working old Wayne-Kerr 6425 in the lab at work, and I am pretty sure also a box of SX72’s.  But away for the next 2 weeks.  If not solved by then send a note and I will dissect one for measurement.  That machine may be old but in my experience is way more reliable than the modern replacements!

I agree that the GP20Na probably has its origin in the German Osram / Narva spectral series, and the Russian DNaS 18.  It’s very difficult to know which came first though.  During the 1940s German Osram and its former East German special lamps plant which was captured by the Soviets and became Narva, were both severely weakened.  The vast majority of Osram’s production machinery had either been destroyed, or disappeared when it was packed onto railway wagons for transport to the West and to the controlled Philips factories - but never arrived.  It was presumed that those trains were accidentally sent the wrong way, and seized by the Soviets.  It took almost another decade for Osram to gradually resurrect even its general lamps production, before getting back into making the specials.  During that time that time the Soviets surged into the lead, based on the machinery and technical know-how they had acquired from Osram - and also from Tungsram Budapest whose factory was completely emptied of all machinery.

Certainly by the 1960s, the GP20Na was being produced in Japan - which had very close links to the Soviets from whom it imported many lamp technologies.  I have quite an old Toshiba GP20Na.  That is almost identical to the Russian DNaS 18.  China acquired a lot of its mid-century lamp technologies from Moscow but also from Japan.  The latter seems perhaps more likely in this case since the name is the same as used in Japan.

For sure the German/Soviet/Japanese/Chinese design is much simpler than GE’s NA-1 and the older Philips equivalent, however the latter seems to have superior intensity.  It should also be remembered that the USA has an unusual attitude of sometimes leaving a design alone when it works well enough, even though improvements might be possible.  I was shocked when I made my first visits to several of GE’s American plants in the 1990s to see just how ancient some designs were.  For instance I saw their mercury and mercury-cadmium Lab-Arcs were still in production in 1997 with the exact same design as the 1940’s!  The plant engineer laughed that the quartz arc tube seals had been upgraded around 1950 for the general lighting versions - but the profits were so huge on the Lab-Arcs, and there was no real competition, so it was absolutely not a priority to upgrade the design.  It would likely have cost more than the saving, due to the low production volumes. 

It must also be remembered that from the 1950s onwards GE did not sell the NA-1 itself - the business was handled via George W. Gates.  The latter had probably made so many fixtures, in use at every high school and college across the country, that it would have been inconvenient to change the design.  For GE also that would have risked a competitor getting into the market, whereas by sustaining its old design it was assured of a healthy and almost endless business of replacement lamp sales.

Whenever I am trying to determine an appropriate step up transformer for running HID reactor ballasts, should the transformer size in volt amperes (VA) be determined by multiplying the ballast’s line current at startup by the ballast’s input voltage or should I multiply the ballast’s line current when the lamp is fully warmed up by the ballast’s input voltage?

For example, one of the fixtures that I am looking at uses a 200V 60Hz high power factor reactor ballast for 250W mercury vapor lamps.

According to the data I have gathered, the ballast’s startup current is 2.5A and the ballast’s current when the lamp is at full brightness is 1.4A.

However, if the ballast has no power factor correction capacitor, the startup current is roughly 3.5A and the line current when the lamp is at full brightness is 2.1A.

Reference data sheet for 250W high power factor reactor ballast:

https://www.akaricenter.com/suigin_kouatu/iwasaki/anteiki/pdf/H25CC2A352.pdf

Reference data sheet for 250W low power factor reactor ballast:

https://www.akaricenter.com/suigin_kouatu/iwasaki/anteiki/pdf/H25C2A352.pdf

During a collectors' meeting in Germany, a hobbyist friend showed me a mercury vapour lamp of the type HQLS 250W, which was undoubtedly manufactured by NARVA in East Berlin in the GDR in the second quarter of 1967.



The special thing about this mercury vapour lamp is the fact that the name NARVA is missing on the lamp base and has been replaced by the name ‘Olompia’. I was completely unfamiliar with this name.



It is the first lamp manufactured by NARVA that I have ever seen with this unusual trade mark.

Who knows this name ‘Olompia’ and for what purpose (perhaps export) was it used?

I've seen green argon indicator lamps.
Adding mercury would create a bluish halo around the pinkish neon-argon glow.

The only argon glow lamp I know of is the AR-1 lamp, which was really only used as a small UV/blacklight source with a high purity glass envelope, never as an indicator. If you can indeed strike a discharge in argon with 120V, why was this never incorporated into small scale neon bulb style indicators?

Also, if you added mercury to a normal neon/argon penning mix indicator lamp, wouldn't that make it brighter/more efficient (and blue)? Why was this never done?

Thanks for the template, but how would I know if the streetlight is utility-owned or municipality-owned? Most of the streetlights are QL Series 114 streetlights, and I have a feeling that Commonwealth Edison wouldn't install them, opting instead for GE streetlights, since all the streetlights I know of that are utility-installed are GE models.

Hi [xyz],

I noticed these lights were out. If possible, I would like to save a few.

[Description of said light (HPS, MV)]
[approximate location / nearest intersection or house number]


etc.

That's how I got my OV-15...
But there's a catch. That only works when the TOWNSHIP owns the lights, rather than the local utility company. Being that the lights near me are all township owned, it's all one or two guys replacing fixtures for LED throughout the township.

Hope that helped.