Watt ? Candle Power... ?

[lxdude]

It sits on the wall and you pick it up when you need to use it.

So if I had one, I could use the toilet without having to get up from the couch? Cool!

 

[Steve Smith]

So if I had one, I could use the toilet without having to get up from the couch?

If you like!

You say that you can't see the flicker? I can tell you how you can see it.

Getting back to this 50/60Hz flickering. I find it hard to believe that a piece of tungsten glowing white hot will cool down and heat up enough in 1/100 of a second for it to be noticeable.

Perhaps with LED lighting (except that it is probably converted to DC internally) and florescent lighting but certainly not tungsten.

This works in the US, not sure about other places.
When Electricity is generated it is produced on 2 sides of the generator

In the UK and most of Europe (I think) electricity is generated in three phases rather than two. I thought it was the same in the US. Don't you sometimes have a separate higher voltage (208v?) supply for things like electric cookers derived from two of the phases?


Steve.

 

[Photo Engineer]

You say that you can't see the flicker? I can tell you how you can see it.

This can get long winded and technical so I am going to try to keep it really simple. This works in the US, not sure about other places.
When Electricity is generated it is produced on 2 sides of the generator, both these "legs" of the power are delivered to your home by the power company and then when your home is wired the legs are used randomly throughout your home. If you sit in a room for a long time that is lit by only 1 incessant lamp doing something like reading then exit that room and go to another room that is again lit one single incessant lamp on the opposite power leg you will notice a slight flicker. You can also sometimes see this effect if you step outside on a dark night with no streetlights on.

Why? Your brain does a lot of really cool things and this is one of them, the light on one leg actually dims ever so slightly 60 times a second, you don't notice because it is slight, and happens quickly. Your brain notices but doesn't tell you and just adjusts to process visual information when it has the most light, this happens over time so you don't notice it. When you move to another space where the light is dimmest when the light in the space you were in is brightest you notice a slight flickering as your brain is trying to catch up and adjust. If you live all your life in 60Hz and are sudden thrust into 50Hz you will notice this as well because you have not developed the timing in tour brain for 50Hz, it will come eventually. If you live in a place where you see both 60 and 50Hz all the time you develop the timing for both.

Oh and if you made it through all that, why not just make some test strips?

AAMOF, it is not uncommon even here in the US for 1/2 of a room to come from one tap and the other half to come from the other half and thus you can have a phase difference within one room. We have exactly this case in our kitchen and it is potentially quite dangerous as you can have 240 V across two different taps.

In Japan, the flicker on the TV was pretty awful, and the picture on the old tube sets was a bit shrunken. The TV sets tended to overheat as well.

PE

 

[Steve Smith]

We have exactly this case in our kitchen and it is potentially quite dangerous as you can have 240 V across two different taps.

As I said before, we have that in just one outlet!

I hope you don't mean tap as in what you call a faucet when talking about voltages in your kitchen!


Steve.

 

[Photo Engineer]

A tap here can also mean a pair of lines from one winding of a transformer. So, typically, our reduction transformers have 2 taps each one at 120 v and 60 cycles, but being of opposite "polarity" in terms of position on the sine wave so that one is high when the other is low giving a difference of 240 v across the span of the tap. It is like an "E" where the top and bottom legs are powered and the center is ground. The voltage across the top and bottom is 240V and across either end and the center ground is 120.

PE

 

[Steve Smith]

A tap here can also mean a pair of lines from one winding of a transformer.

I know. It means the same here and can also mean a single connection rather than a pair. I was just experimenting with comedy!


Steve.

 

[hrst]

We use the 3-phase system, it comes naturally from the generators, and large motors use it naturally. Also, the voltage between any of the phases is 400V, and you get 230V between any phase and ground. No need for transformers at this stage, and less conversions. Higher voltage helps quite a bit with heaters etc. that use large amounts of power. It isn't safe anyhow, so the systems must be designed to be safe. If you wanted to have a safe voltage, we would be below 50 volts AC or 100 volts DC anyway.

Ah, that flicker discussion... Bblhed, are you joking? In case you are not, I would heavily doubt that your brain would have a PLL (phase-locked loop) system to synchronize to a flicker that is only a few percents in amplitude and hard to measure even with electronic devices, and then remember and keep the signal exactly in the correct phase while you leave for the other room. Sorry. The more probable cause is that when you rise quickly, your brain has a little lack of blood and oxygen and gives some minor flicker in your vision, which is completely normal, and you just overanalyze it.

With fluorescents, maybe I would give a thought about it, but even still.......

However, the flicker with fluorescents and how you may get used to it and stop noticing it (or not) is true. And, with 60Hz main frequency (120 Hz flicker), this is naturally harder to notice. Maybe this can be called "synchronizing" but I would call it getting used to it.

Edit: Ah, stupid me! Of course you are wrong. The phase does not matter anything. The bulb generates light exactly in the same way at both half cycles. Unless there is a serious DC offset. Which is a bit improbable, as it comes directly from a transformer.

However, in a 3-phase system, the phase shift in multiple fluorescents can smooth the flicker. But this is because there are THREE phases, not two.

 

[holmburgers]

Fascinating discussion guys,

This bit from hrst, "...but some people report tendency to headaches in strong fluorescent light..." brings to mind the research and work of John Ott; pioneer of time-lapse photography and investigator into the health effects of light on humans & other organisms.

Anywhoo.. Ray? Do you have 50 candles?

 

[Photo Engineer]

Interesting HRST, but I can see a flicker especially when I look off center. I also have problems with my model trains (AC only) unless I have the transformers in-phase with each other. Otherwise I have unpredictable results as I cross insulated blocks.

In fact, I can measure 220 across 2 120 duplex plugs in my home that come from different sides of the transformer outside on the pole. It comes into 2 breakers with different phase in the junction box in our home. At this time, we need to install 2 more breakers from the second transformer outside as our home is beginning to become underpowered due to all of the modern electrical appliances. So, we may end up with 440 broken into 4 120 circuits 2 in-phase and 2 out of phase. IDK. I have to talk to the electrician and this job is going to be expensive.

PE

 

[Ray Rogers]

The whale said: "Oh no, not tonight... I have a headache!"

Yes very interesting comments...

50 candles? You thought of that too, huh?
Unfortunately there are twists and curves...
and probably way beyond my capacity to wade through...

You see, it can't be just any candle!

According to our Wiki Wisdom:
This Candle is one...

"...originally defined in England by the Metropolitan Gas Act 1860 as the light produced by a pure spermaceti candle weighing one sixth of a pound and burning at a rate of 120 grains per hour."

And naturally, "Spermaceti is found in the head (?!!) of sperm whales...."

So, where does one buy whale sperm these days?
And how to make a spermcandle?

Ray

---
Grumbling:
Other problems wiki points out but stops way short of solving:
In 1921, the Commission Internationale de l’Eclairage (International Commission for Illumination, commonly referred to as the CIE) redefined the international candle again in terms of a carbon filament incandescent lamp.

In 1937, the international candle was redefined again against the luminous intensity of a blackbody at the freezing point of liquid platinum which was to be 58.9international candles per square centimeter.

Since 1948 the term candlepower was replaced by the international unit (SI) known as the candela. One old candlepower unit is about 0.981 candela.

Less scientifically,
modern candlepower now equates directly (1:1) to the number of candelas —
an implicit increase from its old value."

 

[Photo Engineer]

Ray;

I think you have your French wrong. A Sperm Whale has nothing to do with "sperm". So, this is Sperm Whale "fat" from the head of the whale.

Good luck.

PE

 

[Hexavalent]

...

"...originally defined in England by the Metropolitan Gas Act 1860 as the light produced by a pure spermaceti candle weighing one sixth of a pound and burning at a rate of 120 grains per hour."

And naturally, "Spermaceti is found in the head (?!!) of sperm whales...."

So, where does one buy whale sperm these days?
And how to make a spermcandle?

Ray

Lab grade spermaceti wax - get busy Ray, we want results!

 

[holmburgers]

So, where does one buy whale sperm these days?
And how to make a spermcandle?

Ray;

I think you have your French wrong. A Sperm Whale has nothing to do with "sperm"

This is why I commit so much time to APUG... for these gems

 

[Ray Rogers]

Ray;

I think you have your French wrong. A Sperm Whale has nothing to do with "sperm". So, this is Sperm Whale "fat" from the head of the whale.

Good luck.

PE

Yes. Very interesting!
(I did not imagine they actually stored their sperm in their head... see below)

I've not looked up the history of the words, but there is some curious issues...

First, Which came first?

Second, I've only recently noticed that sexual organs (male?) are now sometimes refered to as "junk" which yes indeed, is another word related to these whales and their spermaceti.

Third, Whales are mamals with a lot of this "spermaceti" in their heads, right?
Well, I have known a lot of photographers who think more with their penis than they do with their brain... judging by their subject matter and general focus!

So perhaps there is more to it... in fact, I know there is another chapter here!

I am egar to do... "The Rest of the Story".

 

[Photo Engineer]

Ray;

Write a book. They are so much fun to do and so easy to write! (Yeah, sure!)

PE

 

[lxdude]

Ray;

Write a book. They are so much fun to do and so easy to write! (Yeah, sure!)

PE

It's sure to be a seminal work.

 

[outwest]

Ray, to get back to your question of what people are using for AZO and Lodima, I use a 40 watt bulb in a metal reflector at 4 feet.

 

[c6h6o3]

I use a 300 watt bulb at 3 ft.

 

[Steve Smith]

I use a 9.4 × 10 to the power of 16 watt hydrogen powered lamp at a distance of about 92,957,130 miles.


Steve.

 

[Photo Engineer]

Brilliant Steve!

 

[Worker 11811]

How many candle power do you think that is?

 

[Kirk Keyes]

I use a 9.4 × 10 to the power of 16 watt hydrogen powered lamp at a distance of about 92,957,130 miles.

OK, now what's that in metric?

 

[c6h6o3]

OK, now what's that in metric?

The Watt is an SI unit of measure (1 Joule / second) so all we have to do is convert statute miles to kilometers. So, he's using a 9.4 × 10 exp 16 watt lamp at a distance of 149,599,999.42272 kilometers.

 

[holmburgers]

Anyone know how to quantify 800fc/sec?

 

[SkipA]

holmburgers, I presume you are referring to Kodak's instructions for cine film reversal? Kodak says 8600 lux-seconds in the tech sheet for TRI-X Reversal Film 7278. Kodak added a note that it is "~800-footcandle seconds. A 10-second exposure to a common 60-watt lamp at 12 to 18 inches."

EASTMAN TRI-X Reversal Film 7278

H-24 Processing Modules for Motion Picture Films

H24 Module 15 Processing Black-and-White Films