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  1. #31
    Steve Smith's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    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.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  2. #32
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    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.
    Last edited by hrst; 03-27-2011 at 05:14 PM. Click to view previous post history.

  3. #33
    holmburgers's Avatar
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    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?
    If you are the big tree, we are the small axe

  4. #34
    Photo Engineer's Avatar
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    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

  5. #35

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    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."

  6. #36
    Photo Engineer's Avatar
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    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

  7. #37
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    Quote Originally Posted by Ray Rogers View Post
    ...

    "...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!
    - Ian

  8. #38
    holmburgers's Avatar
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    Quote Originally Posted by Ray Rogers View Post
    So, where does one buy whale sperm these days?
    And how to make a spermcandle?
    Quote Originally Posted by Photo Engineer
    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

    If you are the big tree, we are the small axe

  9. #39

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    Quote Originally Posted by Photo Engineer View Post
    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".
    Last edited by Ray Rogers; 03-27-2011 at 11:43 PM. Click to view previous post history.

  10. #40
    Photo Engineer's Avatar
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    Ray;

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

    PE

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