Why do street lights flicker in snowy weather?

I presume "wall temperature" is the temperature at the inside of the glass tube right next to the glass.

I'd no idea that these lights operated at such high temperatures - even hotter that an indcandescent light. I tend to think of discharge bulbs as being "cold" compared with incandescent, but evidently this is not always the case!

Reply to
Martin
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Incandescent lamp filament is about 2700K, which is quite a bit hotter than these arc tubes.

When you switch off a HID lamp (mercury, sodium, ...) the electrodes and arc tube are glowing bright red hot until they cool down.

Reply to
Andrew Gabriel

Yes but the wall temperature (well, the outside wall, anyway!) isn't that hot.

Are they? Didn't know that. How hot are the electrode tips for an arc light?

Reply to
Martin

The color temperature of the light emitted, and the operating temperature of the bulb are two entirely different and unrelated things. Light bulb nomenclature, when referring to a temperature measured in Kelvins, is referring to the light color temp, not the operating temp of the bulb or filament.

Reply to
lurch

With tungsten incandescent lamps, the filament temperature and the color temperature of the emitted light are about the same. Color temperature refers to the temperature of an ideal incandescent radiator (namely, a "blackbody") producing light of the color temperature in question. The color of light from incandescent tungsten is not much different from the color of light from a blackbody at the same temperature.

- Don Klipstein ( snipped-for-privacy@misty.com)

Reply to
Don Klipstein

The temperatures quoted are for the wall temperature of the arc tube. The arc tube is contained in an outer bulb that operates at much lower temperature.

Reply to
Victor Roberts

I used to make a black body source that used a foot long calibrated filament.

I used to make another that used coils of 'coiled' heater wire wrapped around the ceramic 'wool' wrap and silica 'plaster of paris', then we wrapped around the outside of that. The base form inside all of it was a basketball. After the form set, we bake it in a kiln and after that, with the actual excitation coils. Put a foot long ceramic feeder tube onto that, and one "looks" into a perfect black body cavity.

Those were fun to slather together, and quite profitable too.

Reply to
lurch

Eddie wrote: ...

At the start of the cold period, my house lights and those of a friend, both also in SE England, flickered a few times. I assumed the weather was affecting overhead power lines somewhere, which resulted in automatic switches having to transfer load.

Colin Bignell

Reply to
Nightjar

-------- In no way did I imply otherwise. However a generator is either on line or off line as a unit so that the system "capacity" changes in blocks depending on the rating of the machine added or removed from the system. The system "demand" depends on the load and this demand is split between the units on line- generally through some economic dispatch scheme.

-------------------- I am quite familiar with the concepts and practice involved.

-----------------

Again I have no problem with this- this is normal . Possibly there are some word usage problems

I take capacity as the total available generation on line That is, (ignoring power factor as it affects unit capability), if there are 2- 100MW units and a 50MW unit on line the capacity is 250MW . The load and losses (again ignoring pf) may be 200MW leaving 50MW on-line reserve. I take demand in this case as the load +losses 200MW which has to be delivered to the system. Except for transient periods when loads change the supply and demand are the same. Only during acceleration or deceleration will they be unbalanced. Typically generator droops, essential to proper load sharing between units, will result in speed changes. These lead to frequency errors and the need to correct the long term average frequency.

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In my opinion, wind is to be used when available- reducing the load on other sources at that time- but it doesn't replace the other sources for the good reasons that you have given. The fact that wind energy is available on nature's timetable, not man's, is one that many wind advocates appear to ignore.

Reply to
<dhky

Doesn't that sort of thing happen when intermittent shorting or arcing trips a breaker somewhere and the breaker makes automatic re-tries ?

Derek.

Reply to
Derek Geldard

I would describe such events as a bit more than a flickering.

Reply to
lurch

? ?????? ??? ?????? news:6dxXm.99441$ snipped-for-privacy@newsfe08.iad...

*plonk*
Reply to
Tzortzakakis Dimitrios

Excellent eco-weeny response there. Stick your fingers in your ears and refuse to listen to hard fact.

Reply to
Steve Firth

What would you expect from someone original enough to give his name and address as noone@nospam?

Reply to
Androcles

The refutation of his, and any windmill enthusiast's claim that windmill are going to reduce CO2 emissions is to look at countries which have an aggressive policy of installing windmills. Say Germany.

Compare Germany (lot so windmills) to France (very few windmills, lots of nuclear power). Germany emits about 10 tonnes of CO2 per person per year. France about 6.5 tonnes per person per year.

Similar levels of industrialisation, similar climates, similar everything. What the Germans have found (surprise, surprise) is that wind power is unreliable and must be supplemented by conventional generating capacity.

The UK could meet all its Kyoto obligations by going nuclear to the same extent as France. Politicians in the UK are too wet to go for it.

Reply to
Steve Firth

British citizens nowadays carry drugs into China to get themselves executed; they have good ol' Gaelic, Cymru or Anglo-Saxon names like "Akmal Shaikh". I'm surprised Gordon Brown isn't wearing a turban to get himself re-elected.

Reply to
Androcles

I know this is going to be hard for you to understand. But the use of the plural in that phrase was inappropriate, and the use of "citizen" is dubious. I think the term you were looking for was "subject", singular.

I think you will find his aim was to make lots of money, not to get executed.

As opposed to good old American names like "Nidal Malik Hasan", "Mohammed Ali", "Barak Obama" or "Androcles" you mean?

Turbans are worn by a very small proportion of the UK population, notably Sikhs who are not Moslems and who are not even the majority in the immigrant population. Your own coutnry appears to have an immigrant population of about 250 million. So if you're one of those tossers who bases their entire politics on the status of someone as "an immigrant" then I suspect you'll have to start by hating yourself.

Oh look. You already do.

Reply to
Steve Firth

I know this is going to be hard for you to understand, but Britain has citizens that are not subjects.

formatting link
forms of nationality are:

§ British citizenship; § British overseas citizenship; § British overseas territories citizenship; § British national (overseas); § British protected person; and § British subject.

Which demonstrates his intelligence.

"Androcles" is pseudonym. Good 'ol boys in the USA claim

any European ancestry but French. That's probably down to the

French and Indian wars and the Louisiana purchase.

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My own country has a population of 61,126,832 (estimated). How many does

yours have?

I'm not such a wanker as to presume to know your nationality;

I can guess from %steve%@malloc.co.uk but you could be a

wog ("Worthy Oriental Gentleman" in Foreign Office parlance)

that understands memory allocation. Do you have a corresponding

@free.co.uk?

Reply to
Androcles

Mr Shaikh was a subject. Perhaps you should try to remember what you are talking about?

I see you dodged away from the fact that he was an individual, not a group. Is coping with the difference between singular and plural something that confuses you?

Reply to
Steve Firth

According to the BBC news he was citizen. Perhaps you should contact Auntie Beeb and correct them.

Is coping with data that contradicts your assertions something that confuses a tosser like you so that you have snip it to ignore it? Oh look. You already have.

formatting link
forms of nationality are:

§ British citizenship; § British overseas citizenship; § British overseas territories citizenship; § British national (overseas); § British protected person; and § British subject.

Which demonstrates his intelligence.

"Androcles" is pseudonym. Good 'ol boys in the USA claim

any European ancestry but French. That's probably down to the

French and Indian wars and the Louisiana purchase.

formatting link

My own country has a population of 61,126,832 (estimated). How many does

yours have?

I'm not such a wanker as to presume to know your nationality;

I can guess from %steve%@malloc.co.uk but you could be a

wog ("Worthy Oriental Gentleman" in Foreign Office parlance)

that understands memory allocation. Do you have a corresponding

@free.co.uk?

Reply to
Androcles

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