LPS SOX Sodium Lamps

[trencheel303]

I just about managed to squeeze some of the blue and green lines from the SOX lamp. I had to attenuate the yellow light by using one of my OD2.5 eagle pairs and cranking the camera settings right up. Not sure what the multitude of yellow lines is about, but I am using a CD after all and I was quite close to the lamp.

To my own eyes with the eagle pair the spectrum really just looks like a muted version of the SON spectrum without any of the red and far less distinction in the blue. The green is there though, if you look very closely between the two yellow lines you can see a hint of green. The two blues are there, possibly from Argon and also the weak turquoise sodium line. I think the SOX lamp in this lantern is quite new so there will still be plenty of argon left in it, possibly the reason for this line being as prominent as it is, considering.

 

[Sigurthr]

The duplicate lines are the additional orders the diffraction grating (CD) produces. I'm not sure what manufacturers use argon in their penning mix, but my 35W doesn't show any characteristic argon lines (and I have a pure Ar electrodeless tube to compare it to), even during startup. There's no one mix for all makers, so it is very possible.

You may want to pick up an inexpensive spectroscope for light source qualitative analysis. I have one just like this and it works quite well if you calibrate the slit size and position. Eisco Premium Quantitative Spectroscope | eBay

FWIW I could never get a CD to give me a good spectrum, the lines are always highly curved arcs with inadequate spacing.

 

[trencheel303]

Yeah it's really a bit of a botch that I remembered when busman2 was trying to identify lamps in his locality. It's a botch that sorta works but gave my otherwise mundane evening a highlight

In a SOX lamp the argon is always there, it's just a small amount that is mixed in with the neon. This helps bring the strike voltage down to something practical as I'm sure you know. I'm also fairly sure the argon mixture is what helps it strike particularly cold weather.

Here's a good link I found: The Low Pressure Sodium Lamp

That Spectro is also very cheap. I do think I will end up getting a spectrometer as I would definitely use it.

 

[Sigurthr]

Interesting. I'm surprised since Ne has a much lower breakdown voltage than Ar. That link says it is quite a low percentage, so it's entirely possible the Ar lines are just swamped out of my vision by the stronger Na and Ne lines.

 

[Cyparagon]

sigurthr: "360mA which is spot-on perfect" That's the peak value on your scope screen. Aren't the current ratings in RMS, though?

I'm having a hard time tracking down the operating current for an 18W SOX. Some places say anywhere as low as 250mA and others as high as 340mA.

This source says 360mA.

 

[The Lightning Stalker]

I could be wrong, but all you should have to do is monitor the voltage across the tube and current through
it and adjust until it hits 18W RMS. I did this recently for a 10W LED and then found the actual current
rating online and it was exactly what I had measured.

Cy: Yes everything is in RMS since the tubes are designed to be run on AC.

 

[Sigurthr]

Yeah they're in RMS. 360mApk = 254mArms. After I made the video I went looking to see what the current rating for the 10W and 35W lamps were and noticed a discrepancy in listed current for the 18W unit. I was going off the figures from the seller of the lamp that I ordered, which was "42V @ 0.25A". I didn't think to question it at the time, but that's roughly 10W, not 18. So, either I got a 10W tube marked as 18W, or I'll have to pick up that Fulham 2 to get the extra juice the 18W needs.

Btw, Trench I was looking through that site you posted and there is a lot of good info there. I'd +rep ya if it would let me!

 

[trencheel303]

I've learned something today that I now realised I had misunderstood about SON-E lamps. Apparently they don't plug directly into mercury lanterns with mercury gear as a direct replacement. I'd seen someone refer to them as "plug in SON-E bulbs" and wrongly assumed this. They still require the lantern to be re geared. Learning this has enlightened me but potentially scuppered a project I had lined up to share a ballast between an MBF and SON bulb.

 

[DashApple]

I have 3 of the 200W SLI/H SOX lamps ,

I tested them with 4 Fluro ballasts in parallel ( magnetic type ) and a SOX ignitor across the lamp .

Started straight away , I need to measure the voltage and current arcos the tube , I should be seeing around 1.6A ( 0.4A per Fluro ballast ) though the tube as the 200W SOX lamps need more current than the newer 180W tubes that have a longer discharge tube length .

Only thing I was worried about is if the SOX ignitor would be happy running like this .

 

[Sigurthr]

Got my 18W lamp today. I have it running off the Pony, which started it up no problem. It is being underdriven but not by enough to prevent sodium vaporization. I should get the workhorse 2 in by the end of the week and then I have to rig up a nice fixture for this lamp.

Here she is about 4 seconds after turn on:

Twirly; is your ignitor an in-series or in-parallel type? If it is in parallel, it probably won't care what the lamp current is.

 

[DashApple]

Twirly; is your ignitor an in-series or in-parallel type? If it is in parallel, it probably won't care what the lamp current is.

Ignitor goes in parallel with the lamp connections , Knowing that then I just need to get some more fluro ballasts to put in parallel

Well after I measure the current to make sure its at 1.6A that is .

 

[Sigurthr]

Your previous post reminded me to measure the voltage across the 18W lamp....


33volts AC! Wow, that means that this lamp is running at around 8WATTS! That's nearly half power O_O! Glad I got the other ballast coming!

 

[trencheel303]

Underdriving it for a short time won't be a problem. Just give them nice long runs occasionally, it keeps the penning mixture healthy and stops it from sinking into the glass which happens on continuous short runs.

I'm considering using my 26 Watt'er as a "get the F out of bed" light :crackup:
I need to find a quiet timer though, the grinding noise of the mechanical ones is too much for me.

 

[Sigurthr]

I'm considering using my 26 Watt'er as a "get the F out of bed" light :crackup:

LOL. That would be hilarious, but it might cause some resentment towards 589nm, >.> .

 

[trencheel303]

Look Ma'! It's SOX, in 'Murica!

https://www.google.com/maps/place/L...2!3m1!1s0x808e2a6e84094b17:0xef56762f7ccaef6b

https://www.google.com/maps/@37.328...ata=!3m4!1e1!3m2!1s7WvjcpcyAB0Rp-DG49Spsw!2e0

I'm lead to believe these are in use in some parts of San Jose as Lick Observatory is near by, and they can filter out the light easier. The ones in the top image look like 135 or 180W and are quite similar in some design aspects to the Philips SRS201.

I will say one thing, you Americans certainly know how to design street lighting. I'm a big fan of how your brackets tend to look and I prefer the cobrahead lantern design you guys use compared to the varieties we get here.

 

[Sigurthr]

Yup, the 589nm single line is easy to remove with a single notch filter, same reason they use sodium lasers for observatory guide stars.

Not all of our street lighting is so elegant, in the mercury thread I'll post a google maps of a HPHg not too far from where I live. In the immediate vicinity of my house we have no street lighting at all.