On the smaller lamps in double ended fixtures the UV absorber in the glass also glows blue, visible during start up as the entire glass outer glowing a deep blue before the light from the arc overwhelms it.
Interesting that this one cycles instead of going boom... I'm guessing this lamp wasn't left to go through enough temperature cycles at EOL for the arc tube structure to weaken to the point it would actually be able to rupture since if it's gonna go pop it's normally during startup?
Do these use high voltage like neon transformer voltage to operate? If it's "burned out" maybe you can get it to light using high voltage. I sort of did this with a burned out flashlight bulb and one of those electric hand held bug zapper rackets. It turns the burned out bulb into a strobe light. Some flash so quickly you can use them as a torch.
Yes an No, the Neon sign TX could strike the lamp but the 30 or 60 mA current is not enough to keep the lamp going. It may give nice colour effects. I have a shot with a ballasted MOT and see if that works.
As the lamp ages the internal pressure builds up in operation as the gas fill is heated up hotter, and the voltage drop across the lamp increases. Eventually this voltage is too high for the supply voltage to maintain the arc, and the lamp switches off. As it cools down the pressure drops till the start mechanism is able to start it again, thus the cycling. In many lamps the pressure rises up high enough that the arc tube itself bursts, destroying the lamp. In most lamps as well there is a shorting mechanism for this that simply shorts the 2 terminals, so the starter does not try and get a high enough voltage to arc across the lamp base and cause a fire. Those for use in open fixtures as well have an internal quartz thick glass blast shield so the arc tube rupture does not shower white hot glass all over the area, the rest of the fixtures the housing must be designed to contain this hot glass safely. Sadly many replace the lamp in open fixtures with non safety types, or do not replace the glass front if it is broken, and a failed lamp often causes either damage or injury.
As the lamp gets older the electrodes wear out, the arc gap becomes larger and a much higher voltage is needed to strike the lamp. The lamp goes into a cycling mode as shown here.
The halides can also be absorbed over time by the quartz arc tube (can often be seen when they go purple or green) which weakens it to the point where it blows up! Can be quite violent and most often breaks the outer envelope too.
the coloring of these lamps is amazing
On the smaller lamps in double ended fixtures the UV absorber in the glass also glows blue, visible during start up as the entire glass outer glowing a deep blue before the light from the arc overwhelms it.
0:40 was straight up amazing to watch up close.
Great video! Very similar colours to a sodium lamp going EOL
Beautiful device.
Those where some awesome colours
Interesting that this one cycles instead of going boom... I'm guessing this lamp wasn't left to go through enough temperature cycles at EOL for the arc tube structure to weaken to the point it would actually be able to rupture since if it's gonna go pop it's normally during startup?
Do these use high voltage like neon transformer voltage to operate?
If it's "burned out" maybe you can get it to light using high voltage. I sort of did this with a burned out flashlight bulb and one of those electric hand held bug zapper rackets. It turns the burned out bulb into a strobe light. Some flash so quickly you can use them as a torch.
Yes an No, the Neon sign TX could strike the lamp but the 30 or 60 mA current is not enough to keep the lamp going. It may give nice colour effects. I have a shot with a ballasted MOT and see if that works.
Now that sounds like a great idea for a video. Fry that bulb till it blows up.
coondogtheman1234 we cant really copy photonicinduction, the RUclips algorithm won’t like that very much
Awesome
Is that a 400 watt MH?
The bulb doesnt seem eol maybe you should burn horizontal
What's the End of life condition for arc lamps if I may ask? What is the thing that breaks internally?
As the lamp ages the internal pressure builds up in operation as the gas fill is heated up hotter, and the voltage drop across the lamp increases. Eventually this voltage is too high for the supply voltage to maintain the arc, and the lamp switches off. As it cools down the pressure drops till the start mechanism is able to start it again, thus the cycling. In many lamps the pressure rises up high enough that the arc tube itself bursts, destroying the lamp. In most lamps as well there is a shorting mechanism for this that simply shorts the 2 terminals, so the starter does not try and get a high enough voltage to arc across the lamp base and cause a fire. Those for use in open fixtures as well have an internal quartz thick glass blast shield so the arc tube rupture does not shower white hot glass all over the area, the rest of the fixtures the housing must be designed to contain this hot glass safely.
Sadly many replace the lamp in open fixtures with non safety types, or do not replace the glass front if it is broken, and a failed lamp often causes either damage or injury.
As the lamp gets older the electrodes wear out, the arc gap becomes larger and a much higher voltage is needed to strike the lamp. The lamp goes into a cycling mode as shown here.
Ah yes, that makes sense. Thank you both very much for these explanations! :)
The halides can also be absorbed over time by the quartz arc tube (can often be seen when they go purple or green) which weakens it to the point where it blows up! Can be quite violent and most often breaks the outer envelope too.
The Arc Tube