Streetlight question

[mrSHEiK124]

I notice this sometimes when I'm walking around. Most streetlights have very orange looking light, ~2000K-ish, and are probably HPS / sodium vapor.

Every once in a while I'll see a retarded looking light that is glowing bright white, almost purple, is outputting less light than the bulbs around it, and is constantly turning on and off. What gives?

 

[moshquerade]

do not look into the light :light:

 

[FoBoT]

maybe is it broked

 

[mrSHEiK124]

Paging Geekbabe?

 

[Colt45]

sodium is purpley when it first strikes... when it's weak, they keep starting / stopping, and hence stay purpley

 

[mrSHEiK124]

Originally posted by: Colt45
sodium is purpley when it first strikes... when it's weak, they keep starting / stopping, and hence stay purpley

Aha. Thanks

 

[Rubycon]

Originally posted by: mrSHEiK124
I notice this sometimes when I'm walking around. Most streetlights have very orange looking light, ~2000K-ish, and are probably HPS / sodium vapor.

Every once in a while I'll see a retarded looking light that is glowing bright white, almost purple, is outputting less light than the bulbs around it, and is constantly turning on and off. What gives?

High pressure sodium lamps use a ceramic arc capsule. The sodium "fades" over time causing the arc maintenance voltage to increase beyond the output of the ballast. When the arc extinguishes the process repeats itself. The arc will not strike until the capsule has cooled considerably. A cold tube will have a purple colored glow due to the mercury that's used to assist in starting. As the heat builds additional sodium ions become available and the light output turns more yellow-ish in color. A healthy bulb builds up from a cold start in about five minutes. Re-strike time after a power interruption can be anywhere from 10 seconds to five minutes depending on the ballast/ignitor system used.

To summarize - a cycling HPS light indicates that a re-lamp is necessary.

 

[FoBoT]

rubycon posts the highly technical answer, i think i was still right, for the OT answer

 

[Jeff7]

Also of interest

Sodium vapor lamps, especially low-pressure, have some really crazy spectrums. Lots of red and green, but not much blue.

High Pressure Sodium lamp, from GE [Lucalox 35W]. Note complete self-absorption of the sodium D line and thermal broadening of additional sodium lines. Color temperature @ ~ 2,100K. Efficiency: 100 lm/W. CRI: 24. These lamps are the light source of choice for large public spaces because of their increased efficiency, therefore they are the most used light source for street, highway, garage, warehouse, shipyard, refinery, heavy industrial space and airport lighting.

Color Rendering Index: 24. Pretty damn lousy.

 

[Black88GTA]

"I'm going to take care of that street lamp sk0t style"

 

[rudeguy]

Originally posted by: FoBoT
rubycon posts the highly technical answer, i think i was still right, for the OT answer

Negative.

The correct OT answer would be that DnOR shot flaming ants out of his penis and hit the hot chick across the street. She was starting to scrape off her car but because one of the ants hit her in the eye, she jumped in the car without scraping off the top. When she was driving down the highway, a piece of ice flew off the top of the car and it a passing Audi TT. The TT driver was on his way to the mall to pick up some Diesel jeans but instead was forced to stop at the dealership to repair a nick in his windshield. While he was waiting for that to get fixed, he decided to kill some time at Walmart. Now he knew that there was < .9999999% chance of them having his Diesels there, but he figured the 1% was worth checking out. While he was in Walmart he noticed that all of the products there were made in China and that the only customers there were white trash trailer dwellers. He decided that it wasn't worth his time, so he picked up his Audi and headed out. He was heading towards the mall again when he notice the car that had flung the ice at him stopped at a light. He pulled up next to it, ready to give the guy a reaming but it turned out it was a really hot chick and she appeared to be winking at him. He did the honk and wave and it distracted the hot chick enough that she accidentally hit the gas pedal. She hit a school bus full of kids. Luckily it was one of the short buses so all the kids were wearing helmets. But the chick was hurt pretty bad. The ambulance was called and they decided that she needed to be airlifted out. Unfortunately they were surrounded by treadmill stores, so if the medi-vac plane did land, it wouldn't have anywhere to take off from. So the rescue workers decided that they would just take her by ambulance, figuring bater nate than lever.

 

[Rubycon]

Originally posted by: Jeff7
Also of interest

Sodium vapor lamps, especially low-pressure, have some really crazy spectrums. Lots of red and green, but not much blue.

High Pressure Sodium lamp, from GE [Lucalox 35W]. Note complete self-absorption of the sodium D line and thermal broadening of additional sodium lines. Color temperature @ ~ 2,100K. Efficiency: 100 lm/W. CRI: 24. These lamps are the light source of choice for large public spaces because of their increased efficiency, therefore they are the most used light source for street, highway, garage, warehouse, shipyard, refinery, heavy industrial space and airport lighting.

Color Rendering Index: 24. Pretty damn lousy.

LPS hit nearly 200 LPW but CRI is essentially 0. Good for security lighting where vast areas need to be illuminated and color rendition is of secondary concern.

Another neat thing is even at end of life the LPS inner tube still contains enough raw sodium metal for some good old fashioned water in the rainbarrel trick.

 

[mrSHEiK124]

Originally posted by: Rubycon

Originally posted by: mrSHEiK124
I notice this sometimes when I'm walking around. Most streetlights have very orange looking light, ~2000K-ish, and are probably HPS / sodium vapor.

Every once in a while I'll see a retarded looking light that is glowing bright white, almost purple, is outputting less light than the bulbs around it, and is constantly turning on and off. What gives?

High pressure sodium lamps use a ceramic arc capsule. The sodium "fades" over time causing the arc maintenance voltage to increase beyond the output of the ballast. When the arc extinguishes the process repeats itself. The arc will not strike until the capsule has cooled considerably. A cold tube will have a purple colored glow due to the mercury that's used to assist in starting. As the heat builds additional sodium ions become available and the light output turns more yellow-ish in color. A healthy bulb builds up from a cold start in about five minutes. Re-strike time after a power interruption can be anywhere from 10 seconds to five minutes depending on the ballast/ignitor system used.

To summarize - a cycling HPS light indicates that a re-lamp is necessary.

Success! I'm going to call the power company and nag

Did your nick used to be Geekbabe, or is it someone else and am I confused? I know I was looking for you, blonde avatar, always a very technical response....I need caffeine...

Originally posted by: rudeguy

Originally posted by: FoBoT
rubycon posts the highly technical answer, i think i was still right, for the OT answer

Negative.

The correct OT answer would be that DnOR shot flaming ants out of his penis and hit the hot chick across the street. She was starting to scrape off her car but because one of the ants hit her in the eye, she jumped in the car without scraping off the top. When she was driving down the highway, a piece of ice flew off the top of the car and it a passing Audi TT. The TT driver was on his way to the mall to pick up some Diesel jeans but instead was forced to stop at the dealership to repair a nick in his windshield. While he was waiting for that to get fixed, he decided to kill some time at Walmart. Now he knew that there was < .9999999% chance of them having his Diesels there, but he figured the 1% was worth checking out. While he was in Walmart he noticed that all of the products there were made in China and that the only customers there were white trash trailer dwellers. He decided that it wasn't worth his time, so he picked up his Audi and headed out. He was heading towards the mall again when he notice the car that had flung the ice at him stopped at a light. He pulled up next to it, ready to give the guy a reaming but it turned out it was a really hot chick and she appeared to be winking at him. He did the honk and wave and it distracted the hot chick enough that she accidentally hit the gas pedal. She hit a school bus full of kids. Luckily it was one of the short buses so all the kids were wearing helmets. But the chick was hurt pretty bad. The ambulance was called and they decided that she needed to be airlifted out. Unfortunately they were surrounded by treadmill stores, so if the medi-vac plane did land, it wouldn't have anywhere to take off from. So the rescue workers decided that they would just take her by ambulance, figuring bater nate than lever.

:laugh: 10/10
Woulda been 11/10 if you somehow incorporated the OP

 

[Rubycon]

Originally posted by: mrSHEiK124

Did your nick used to be Geekbabe, or is it someone else and am I confused? I know I was looking for you, blonde avatar, always a very technical response....I need caffeine...

No it used to be MS Dawn. You're probably confusing us because of avatars.