More vaguely-informative ramblings about low pressure sodium lamps

Yep. Just talkin' about this thing and low-pressure sodium lights for a bit. Oh and we plug it into the Kill-a-Watt and take a look at its power specs.

[TechnologyConnextras]

Oh hey, I just want to let y'all know (if you haven't already figured it out) that these were all shot in one go and released out of sequence. So when I said "set up the next video, " well you've already seen that one. This is it for the Connextrasvaganza 2021, and I hope everyone has a happy new year!

[PH-G]

LPS lamps are typically used around observatories as their monochromatic light is easy to filter out from images of the night sky more or less eliminating local light pollution while still providing adequate lighting for surrounding areas. The observatory at my school is surrounded by probably about 100+ LPS lights on the nearby buildings and streets as well as the adjacent parking lot. So LPS lamps still have a niche use case at least.

[thirdarc]

This man has absolutely mastered whatever technique it is that he's using to make boring things fascinating.

[JDSileo]

I really like the pace for "low effort" extra content. It's really cool going on the exploration journey with you

[themaritimegirl]

A fun fact you might not know - because they are low-pressure, you can run these on a modern electronic fluorescent lamp ballast, and many enthusiasts do. You get no buzzing, near-zero power loss in the ballast, perfect power factor, and no flickering (which is usually also better for the lamp, as well as your eyes). People often use the Fulham WH2 ballast for the 18W lamps, so I suspect the WH3 would provide enough power for the 35W lamps.

[alasdair]

They must have an extraordinary long life. A car park near my last address had one way up a central pole that was just visible from my house, it was on 24 hours a day for the fifteen years I lived there. One day I enquired at the shopping centre about why it was never switched off and was directed to the maintenance guy. He informed me that the light had a faulty automatic switch and was wired directly to the street supply so nobody had a switch, but as the lamp itself was only 18 watts, nobody had any plans to hire an EWP to repair it until the lamp itself failed.. ten years on from my enquiry and it was still as bright as ever, and it probably lasted a few years longer (I moved interstate), but some of that life may have been a result of staying on without any thermal cycling. I was impressed and always expected it to eventually stay off whenever we had a power failure.. but, it always came back on...
That totalled about 131, 000 hours or more, but who knows how long it was on before I moved there... lol

[millenniumtree]

Hawaii, especially the big island, uses LPS lamps for street lighting, because the narrow emission spectrum is easy to filter out at the observatories on Mauna Kea. Today, they're using LED replacements, that actually still look exactly like LPS. You can tell you've got that spectrum if you have a red car, as we do. The car appears to be grey under an LPS lamp - the red is completely undetectable to the eye, unless some white light hits it from some other source.
When we first visited Hawaii about 8 years ago, the lamps were obviously still sodium. Today, however, I can't remember when I've seen a real sodium lamp - they're almost all LED now.

[Meatball]

These lights are common in many facilities because 1) they last a long time, and 2) they emit a frequency different than other types of light that does NOT attract bugs

[SeanBZA]

Lamp life is the emissive material on the filament failing, and then also sodium attacking the graduated seal that is there where the seal is, as they go from quartz glass to a softer glass that will handle the leadout wires going through, and also allows the vacuum system to pull all the gas out before introducing the Penning gas mix that provides the initial conduction. That is why your standard operating position is base up, or with the base no more than 15 degrees from horizontal, so the liquid sodium does not get near the filament area, and rapidly erode the glass, as it is a sodium oxide, so will dissolve in sodium, unlike the fused silicon dioxide of the rest of the arc tube.

Warm up time is because you have to heat up the inner tube to the point the sodium inside turns to vapour, which is the yellow emission, and the indium oxide coating on the inner surface of the glass envelope and the outside of the quartz tube is there to reflect the IR energy back to the tube.

Ballast is an autotransformer ballast with a tuned circuit in it, and likely the capacitors in there have changed value from self healing, and should be replaced. Identical value polyester motor run capacitors, one by one, and the power factor will improve, especially as the lamp warms to full brightness, and should land up at around 0.85 lagging when on for around 2 hours.

[jeromeprater]

As a kid I remember the prevalence of Mercury vapor street lamps. They glowed a blue white color. It was strange when Sodium vapor lamps became common later on. In some ways the high intensity LED street lamps take me back to the Mercury vapor days at least in relation to the light spectrum they produce.

[jrmcferren]

Here's an interesting fact about LPS lamps. As we all know, as a lamp ages the efficiency decreases. Most lamps have reduced output as the lamps age, but LPS is special. When LPS lamps age, they start drawing more power. I'm not sure how much of your 72 watts is ballast loss and how much is the increase of the lamp, but if you try a fresh bulb you may see a reduction in power consumption.

[christophermoore]

You know, your channel has seriously satisfied my own ADHD-borne need to tear apart and learn about items that I have no time or money to seriously pursue. Every topic seems to emerge just as randomly as the ever changing subject of the never ending question in my head "how does that work?"

You are an inspiration to me as someone who loves learning about how we interact with everyday items!

[karsnoordhuis]

Fun(ish) fact about power factor: because large parts of the Dutch power grid are underground and the ground is rather wet, the ground starts acting as a capacitor and reduces overall reactance.
This means factories can have worse power factors without having to pay like in neighbouring countries.

[raffitz]

The public lighting in my street used to be LPS until very recently. I grew up with a monochromatic orange light at night right outside my window. One of the minor side-effects of this was that in one of your colour theory videos, you said "monochromatic light makes the world look weird" or something to that effect, and to me it was pretty not-weird - it's how the world used to look when I got up to go to the bathroom in the middle of the night for like 25 years.
Now they replaced it with a lower intensity white LED panel, and it took a while to get used to, but it's less weird (no more orange monochromatic world).

[Niei]

I grew up in the 70s and our house was next to an intersection.
When I was around 6 years old I was so fascinated with these bulbs that during the winter months my mum would set up a chair by the window so I could watch them start up.
I still love them as much as I did back then and I have enough bulbs to last me the rest of my life :)

[Josh_Fredman]

Sodium lighting is one of my favorite things. HPS lamps are my all-time favorite lighting source, and LPS are magical in how eerie they are when used out in dark sky regions (e.g., around astronomical observatories). When I lived out there, our cheery red car looked vantablack under them! Loved your videos on this a few years back and happy to see this one today. LPS lamps have been almost impossible to source for at least 3 years now; I'm surprised some enterprising young go-getter doesn't start up a new factory, given the apparent demand.

[Spankyk]

You know this slow warmup is the kind of thing that's actually really nice in low light areas. All of the lights in my house are LEDs now because, well duh. However, two of them are not - the lamps on our night tables in our bedroom still have some old IKEA Compact CFL 'energy efficient' that take an age to warm up because that's *exactly* what we want form our bedside lamps. If you wake up in the night, you don't want to be blinded when you need to turn the lights on. They take several minutes to warm up to full brightness, enough time for your eyes to gradually adjust. I honestly don't know what we'll do when they fail as, as far as I know, there are no LED equivalents with fake 'warm up' time.

[ericdoe]

The streetlight outside of my house is low-pressure sodium, this lamp looked old when i moved into the house 15 years ago. it has to my knowledge never been changed and runs all night long every night.

[gertxsi]

They were very common in the Netherlands over highways en in rural areas. Yes if you aren't used to it, the fixtures containing the 180 watt bulbs look strange. I saved a couple of SOX lamps for nostalgic reasons

[shakeit]

Power factor: I suspect that many who watch this channel have some understanding about reactive and real power, but if you're interested: with a power factor of 1, the voltage and current draw of a component in an AC system (e.g. mains electricity) are in phase, and since power is voltage times current, all the current drawn provides power to the component (real power: we measure this in watts [W]). This is the case for true resistive loads, i.e. their complex impedance have zero imaginary part (imaginary parts introduce phase shift). A resistor is an example of this.

However, with inductive (e.g. electric motors) or capacitive (less common but exist) loads, the voltage and current are not in phase. With the voltage 90 degrees out of phase to the current, no real power is delivered to the load, but it still draws current. One half of the period, the device draws/stores energy; in the other half, this energy is pushed back into the grid. So this reactive power, measured in VA (volt-amperes) to denote that it is not real power, leads to losses in the electrical grid due to current drawn. Every cable has some resistance, and the power loss in the cable is equal to R*I^2. So if the current doubles, the loss is 4 times greater.

The power factor is simply how much of the total current supplied to the load is used to do real work. If the phase angle between the current and the voltage is 45 degrees, cos(45°)=0.707... => 71% is real power and 29% is reactive power. In most countries, you only pay for the real power supplied to your home, but with high reactive power draw, it puts extra strain on the wiring in your house and on the electrical grid, and leads to higher losses.