The lowest voltage I have seen on a 4ft T12 tube is 71V, and that is from a 63W F48T12HO, presumably due to it's current being doubled. A close second is of course the 79V F34T12 energy saving version of F40T12, and that voltage drop is due to there being some krypton in there. Normal F40T12s are around 101V. So that got me thinking.

- Moving from .43A to .8A results in a ~30% decrease in lamp voltage.
- Moving from pure argon + mercury to a specific mixture of argon + krypton + mercury results in a ~22% decrease in lamp voltage.

What if we do both? Meaning have a lamp that is running at around .8A with a krypton+argon fill. I am sure it doesn't work this way, but if we use those same percentages we get 101*.7=71, 71*(79/101)=55.3V. So A 4ft T12 tube with a drop of ~55V. This is almost certainly low enough to be used with a choke on 120V. And what's more is that 55.3V*.8A=44.24VA, so it's wattage (and hopefully light output) is probably very similar to a normal F40T12, just higher current and lower voltage.

And what's more is that these specs are similar to the 37W F24T12HO (41V@.8A), so there might be compatibility there, no need for dedicated new ballast. If not, there is the possibility of using a 35W HPS choke ballast in a preheat configuration (55V@.83A).

Has anything like this been done before? Meaning two fluorescent lamps of identical physical dimensions and similar wattages that aren't electrically compatible? How possible would this lamp be? This seems like something American Fluorescent would've jumped on with their weird preheat-ish shop lights...

I would make a drawing out of this as usual, but there would probably be nothing visually different about it so that wouldn't be so productive.

This is the lamp, it’s definitely not a shielded arc tube. It’s also new-old stock found in my churches basement after they got rid of their high-bays in favor of LED’s.

I personally do not mind a 16% underdrive on most fluorescent and HID lamps as I see this amount of underdrive commonly achieved when 120V inductive ballasts are operated on 110V or 240V inductive ballasts operated on 220V assuming they are operated on their rated frequency.

However, other collectors might not be as comfortable with such underdrives in their opinions.

I am somewhat okay with such underdriving as I have often seen how some lighting enthusiasts and some electricians often interchangeably refer to 120V as “110V” or 240V as “220V”.

I just finally obtained a Japanese low starting current 200V 60Hz mercury vapor reactor ballast for 400W mercury vapor lamps. However, I am not able to find the published capacitance value for its power factor correction capacitor. I would really like some help with trying to determine its capacitance:

https://www.lighting-gallery.net/gallery/displayimage.php?album=lastup&cat=0&pos=4&pid=267299

It would definitely work. The only question is, what would the OSHA guy say when he sees a starter socket rated at 250V used in a 277 V fixture?

Would it be possible to significantly increase MV arc tube efficacy by using an evacuated outer bulb instead of nitrogen filled one? Or does this only work with HPS lamps like the higher pressure xenon fill? I think less power would be required for the smame arc tube temperature (and same mercury vapor pressure) because thermal losses would be reduced. It seems that unlike with MH lamps which oftenuse evacuated outer bulb evan at 400 W and above, with MV lamps this is only used with the 50 W version.

There was a generic 6500K 400W elliptical clear MH lamp at Peamit Store, that exploded despite burned base-up in a highbay fixture: https://www.lighting-gallery.net/gallery/displayimage.php?pos=-251405

Can someone give more details about gas fillings in T5 fluorescent lamps?
I know that the classic 4, 6, 8, 13 W lamps have argon fill, but I'm not sure about others.

There are 11, 15 and 16 W lamps which have the same length as 6and 8 W lamps.
And T5 HE and HO. Is the only diffrence in the electrodes or do they have a different gas filling pressure or even a different gas like krypton?
I know that T8 16, 32 and 51 W 'Eco'(Philips name) or 'ES' (Osram name) have xenon as the buffer gas, so maybe energy saving T5 tubes also have something other than argon. Even T5 HE and HO comes in a more recent energy saving version, like Philips Master TL5 ECO 25, 50, 73 W.

Sylvania B3000 Mk5 to Sylvania RoadLED MIDI

The danger of the radium was highly underestimated back then, but the tendency of the radiation to expose the film was quite a strong argument against, I guess. A brief touch of the paper to the dial and the material would be ruined...