dor123
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@trojmiejski: See my comment in your picture. This isn't looks like lamp EOL to me.
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.
I only working with the international date format (dd.mm.yyyy).
I lives in Israel, which is a 220-240V, 50hz country.
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trojmiejski
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| Seen the reply. There is mechanism which leds to Na pressure increase near EOL. When arctube is severely blackened, the soot reflects radiation back into the arc, heating contents more than they would normally do so which in turn increases pressure. It's similar how SOX lamp without indium-tin oxide IR reflective coating won't fully heat up, difference is in SOX lamps we want this while SON lamps aren't designed to operate at such elevated parameters.
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dor123
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| This definitely don't looks like pinkish white associated with HPS lamp near EOL. SDW like light is definitely not a problem with the lamp.
When the sodium is lost from the arctube, the mercury IS the element that its pressure increases, hence the redder or pinker color of old HPS lamps, and they starting bluish mercury.
The sodium line actually gets narrower and widens only in the red.
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.
I only working with the international date format (dd.mm.yyyy).
I lives in Israel, which is a 220-240V, 50hz country.
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trojmiejski
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| If sodium is lost then yes, mercury-sodium ratio changes and lamps becomes redder. But that's true IF sodium is lost, this may not always happen. Some lamps may blacken severely while retaining most of sodium as originally dosed. Then pressure and lamp voltage will increase. The lamp on the photo was near EOL because in the next days after taking that photo it went completely dark. Later in different city I saw another HPS that produced warm white light and some time later I've seen it leaked into outer bulb.
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dor123
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@trojmiejski: You have read what I wrote in my comment on your picture? Only the mercury pressure can be increased, the sodium pressure can't. @RRK and @James: Explain trojmiejski what happening with HPS lamps during life.
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.
I only working with the international date format (dd.mm.yyyy).
I lives in Israel, which is a 220-240V, 50hz country.
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trojmiejski
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| If sodium is lost then yes, the ratio will change in favor of mercury. However if there won't be any sodium loss which may alternatively happen, then amount of sodium molecules dosed into arctube remains same, amount of mercury same but per PV = nRT equation the rising temperature of blackened arctube will increase total pressure of the gas.
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dor123
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| This can only occur with MH lamps, not with HPS lamps.
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I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.
I only working with the international date format (dd.mm.yyyy).
I lives in Israel, which is a 220-240V, 50hz country.
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