LPS fixtures, buying used?

[Zelandeth]

Well, it's no big secret really, that my particular area of interest is gas discharge lamps. Heck, not all that many people have a 250W SON-T HPS fixture under a desk in their room...

However, something I do no actually possess is an LPS fixture or lamp, and that's something I'd like to correct.

Especially as it's the type of lamp that first had my reall attention, used to be one at the end of the garden at our old house, and I used to go out there most nights, wait for it to light up, and watch it go through the warmup phase, then happily, return to the house...I was about 6 at the time too!

An old street light head that's been replaced with a newer style (probably HPS or mercury vapor as most of them here seem to be changing to) one, or old security light would probably be my best bet I assume, or am I going down totally the wrong track here? I have next to zero...okay, I have zero cash available here, which is why I'm not even looking at new ones. /ubbthreads/images/graemlins/broke.gif

Basically, what sort of things should I look for in the event of finding a unit (and where on earth should I start looking???), other than the obvious things like line voltage, and that everything's there. In the unlikely even that I'm able to fire it up first, there anything in the behavious of an LPS lamp that suggests a dying tube or ballast? (Like HPS cycling for example) - I'm guessing that tube end blackening is a bad thing, as is an excessively noisy or hot running ballast.
Finally, anyone got a CLUE where on earth I might find one??? /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/help.gif /ubbthreads/images/graemlins/confused.gif


Hopefully this is actually in the right place...thought about putting it in BST, but I;m not actually trying to buy something off anyone here directly...asking advice on doing so...move it if required though.

 

[INRETECH]

Things to look for that are "Bad":

) Discoloration or "spots" on the inside tube
) Oil leaking out of joints on ballasts

HPS tubes are the only non-destructive light source that exist, that is the internal process of the gasses is not used up during the lifetime cycle of the bulb; except for the starting cycle

 

[Chris M.]

Discharge lamps fail in a number of ways. One of the most common behaviors of dying high-pressure lamps (Son / Halide) is to strike, run up then extinguish once almost at full brightness. Give it 10 minutes or so to cool down and it`ll do it all over again. Or they just won`t strike at all, maybe just glimmering round the edges. Low pressure sodium lamps that strike might stay in the red neon phase, flickering like a duff flourescent tube. Or they`ll never fully run up staying red or deep orange. A totally dead one again will not strike at all other than a faint pink glow round the electrodes. The one over the road`s like that right now - I hope they don`t replace it till early next year. It`ll make a change not to have its orange glare cast all over my festive lights display during December!


Most HID fixtures need three things (besides the lamp and lamp-holder). The ballast, the ignitor and the PFC capacitor. They`ll work without the cap but it`s nice to have it there. Low pressure SOX lamp ballasts sometimes have the ignitor built in, epecially the old ones - mine does. Mercury lamps don`t need ignitors, and low wattage ones will actually work with the appropriate flourescent tube ballasts. A 50 watt one I have here runs just fine with the ballast of a 5 foot T12 tube though it`s probably best to stick with proper mercury ballasts incase the lamp ends up over or under-run which could damage it.

You know it already but the excellent lamptech.co.uk has a wealth of technical info about all kinds of discharge lighting including failure modes for some of them, and I know James plans to have such info avaliable for all common types eventually.

Probably the best place to find old fixtures is the council`s streetlighting depot in your town. That light they replaced had to go somewhere, and often there are piles of them just sitting there rusting. Find out where it is, pay them a visit and ask nicely - you never know. They might let you walk off with a few used fixtures and lamps that would otherwise become landfill.

Failing that, wander round the `Net and look for British Streetlighting enthusiast web sites - there are a fair few out there. One of them is Bob Cookson`s - http://www.cooksonr.freeserve.co.uk and several are linked from lamptech.co.uk too. Those guys might know where you could buy some for next to nothing, and may even have a spare lamp or ballast lying around that they might be willing to part with.


Don`t even start looking for brand new ones. They cost big £££s and streetlight heads are not easy to purchase in one off quantities anyway. Radiospares sell an assortment of SON, SOX and Halide fixtures, ballasts, ignitors and lamps but they are all seriously spendy.


/ubbthreads/images/graemlins/grin.gif

 

[Zelandeth]

Thanks for the info!

Guess I'm going to have to try to find where Aberdeenshire council's streetlighting depot is then...that'll be fun...

Might look into a mercury lamp at some point in the future, but it isn't all *that* high on the priority list, LPS is though.

What's the one that you have then with the internal ignitor Chris M?

Hmm....so the search begins...

 

[Chris M.]

<font color="800080">What's the one that you have then with the internal ignitor Chris M?</font>

It`s an old 55 watt low pressure sodium SOX fixture I rescued from oblivion. The lantern had an air gun hole shot in one side and the tube was broken. I was lucky to find another tube at the same place and though the ballast had been out in the rain for a while, it still worked. The insides are now up on top of my wardrobe. Not used too often for obvious reasons but I do light it now and then.

I can`t remember the brand of the ballast, it could be Osram but it`s hard to get at so I¬m afraid I can`t have a look.

/ubbthreads/images/graemlins/grin.gif

 

[Zelandeth]

Okay...let's try that again...ever noticed how getting a straight answer out of a council is NEVER easy...I am going to find out where that depot is...and that's that...someone in their headquarters MUST know!

 

[phyhsuts]

Osram makes a darkroom light that uses a 18W LPS lamp. No idea what it costs, but that is likely to be the easiest LPS light you can get.