street lamp ballast

[Fred]

Hi,

Whilst helping the relatives have a spring-clean, I found an old exterior light, it is rather like a street lamp, so more commercial/industrial than domestic. It looks as thought the fitting is largely made of aluminium, so I was hoping to take it to the scrap man.

I think they may be sodium lamps as the bulbs look something like a BC version of this:

notice the description says "golden white" whatever than is! I thought they were orange.

Inside the fitting is a large (in terms of size, not capacitance) capacitor and a heavy metal ballast. The ballast is a sealed unit. Does it have an iron core? Is that why it is so heavy? I'm just wondering what bag to throw it into to take to the scrap yard. Do I throw it in with all the steel? Perhaps I should angle grind it open to see what's inside?

TIA

[Brian Gaff]

Copper wire round some form of core. Depends on the design. Could be ferrite, laminated iron... Brian

[meow2222]

The ballast is copper wire on iron core. Sell the whole thing, silly to scrap it

NT

[meow2222]

Its high pressure sodium, and yes, golden white is a euphemism for orange-pink.

NT

[Martin Brown]

It is probably worth more to someone who wants an HPS lamp and fitting! (at least if it is functional)

The old magnetic ballasts are not as good as the latest solid state in terms of efficiency but they are still pretty good.

> I notice the description says "golden white" whatever than is! I

Golden white or peachy white is the colour of a typical HPS (high pressure sodium lamp) - you can get sort of lemon yellow white. They strike yellow and rapidly turn creamy whitish.

The orange ones are low pressure sodium and emit more or less all their light in the sodium D-lines. They strike red and gradually turn yellow as they warm up. They are preferred street lighting in the vicinty of professional optical observatories. Declaring an interest here as I sell sodium light blocking filters to amateur astronomers:

the spectra of the most commons street lamps and the effect of various astronomical filters on them.

You might want to keep it as an outside light if it is actually working

- they are far more energy efficient than other sorts.

[meow2222]

Yes - but 250w of 120lm/W or so is a monstrous amount of light, around 30,000 lumens. Good for a greenhouse.

NT

[harry]

SOX lamps are orange. SON lamps are yellow. The ballast is a copper coil wound on to an iron yoke. There may also be and ignitor that starts the lamp.

[F Murtz]

>>>>> I notice the description says "golden white" whatever than is! I

Keep it and grow marijuana hydroponically.

[Andrew Gabriel]

shape is a standard equi-thermal bulb (the shape you end up with if you want the bulb to be similar temperature all around the enclosed short arc tube, ignoring convection heating).

I've never seen a BC high pressure sodium lamp, or BC on any equi-thermal bulb, because a BC lampholder can only support that weight and size of lamp when hanging cap-up. It was used for some early mercury vapour lamps with more conventional (GLS/pear-shaped) lamps, for use in cap-up fittings, including self-ballasted ones with internal filament ballasts, but yours has an external ballast (and no external ignitor, at least, you didn't mention one).

BC is also used for low pressure sodium lamps, but the lamp has an additional bulb support in this case, being long tubular in shape, and (almost) clear glass.

So it would be interesting to know all the markings on the lamp, and a picture, and same for the ballast, and lantern.

Sodium can be anything from orange through to warm white, depending on the arc tube operating pressure and other doped elements included.

It probably has more resale value than scrap value.

[Fred]

I'm not sure whether it does work. It was buried in the back of a shed and had not been used for some time. I was going to wire it up to see but then I thought I've got so many other things that I've never got round to doing that perhaps I should not make another job for myself!

Thanks. I had forgotten there are two types of sodium light. I was thinking of the ones that used to be used in street lamps, that strike red and glow orange. I went along a stretch of motorway the other week that was lit by these and it looked so strange because I have become used to "white" street lighting.

Thanks.

[Fred]

I used to be interested in different shaped light bulbs when I was young. It's a shame I lost interest as I grew up. It must be an interesting industry to work in.

I have had a closer look. There is something printed on the bulb but all I can make out is "Phillips"; the rest is too faded to see. It seems it is not a BC cap but actually has pins at right angles, a bit like a car brake light. I've taken a photo for you to see. You may be able to see a little of what is inside the glass, if that helps identify it?

As for an ignitor, I have no idea what one of those is so I don't know if it has one. There seems to be a patch on the "ballast", if I am using that word correctly, as if a label used to be there but it is long gone, so I can't tell you more I'm afraid.

The capacitor label, not the best photo, sorry, says it includes a resistor and a fuse.

The lamp:

bulb: don't know if any of those help at all?

Thanks.

[meow2222]

I've seen those 3 pin bases before, if that's what it is, but don't know which type of light it is. I'd ebay it as seen, calling it a 250w hydroponic lamp, explaining where it came from, and that its either sodium or mercury.

NT

[polygonum]

type of light it is. I'd ebay it as seen, calling it a 250w hydroponic lamp, explaining where it came from, and that its either sodium or mercury.

British Rail, at least on the Waterloo-Portsmouth line of Southern Region, used three pin BC tungsten lamps in carriages. (Might have been Class 404 - and might have been far more widespread.)

[Andrew Gabriel]

It's an obsolete mercury vapour lamp, probably 80W or 125W. They were retro-fitted into filament lamp luminares in the 1950's and 1960's. They came in two types, standard BC which is a direct plug-in replacement for the filament lamp, as the lamp has a built-in ballast in the form of a tungsten filament, and the separately ballasted type you have there which required the lampholder to be changed, to prevent the two types of lamp getting mixed up (your one would explode if plugged into a streetlamp with no ballast fitted).

Mercury vapour lamps don't need an ignitor. (If it was high pressure sodium, it would have, some smaller lamps have it inside the bulb, or it can be external).

That looks like a 1950's one. There are streetlighting forums where a collector would be able to tell you the make and model from your picture.

envelope of the "lamp".

Datasheet values I have are 8MFD for 80W, and 13MFD for 125W, but the capacitor value doesn't matter at all for correct operation, only for power factor correction of the supply current drawn.

[meow2222]

ebay calls

NT

[Andrew Gabriel]

I suspect a streetlamp collector would like it, although it isn't one of the most interesting types. I don't know if ebay is the best way of connecting with them.

[Weatherlawyer]

,000 lumens. Good for a greenhouse.

Brilliant for growing wacky backy. Should get a customer quite easily.

[Jules Richardson]

FWIW, I think there are traces of a number to the left of the first zero

- pissing around with the contrast on the image, I think it's most likely a 4, but it's very hard to tell with a high degree of certainty.

cheers

Jules