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Windmill

Discussion in 'Electronic Basics' started by Rodney Kelp, Jun 15, 2004.

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  1. Rodney Kelp

    Rodney Kelp Guest

    With wind speeds from zero to tornado, how do windmills maintain voltage and
    more importantly frequency when hooked up to a grid? If they put out 3 phase
    there must be a phase sync problem.
     
  2. Art

    Art Guest

    Governor as per speed control and adjustable pitch props, DC output into a
    DC to AC Converter that automatically adjusts the phase and voltage output.
    Otherwise they would either physically destroy themselves and the internal
    gear train when over revved by extreme winds, etc and of course, if the
    voltage output were dependent on the rpms of the prop shaft, that too would
    vary immensely.
     
  3. hotkey

    hotkey Guest

    they change the angle of the wings, untill unsafe when they switch off
    altogether
     
  4. Lord Garth

    Lord Garth Guest


    Long ago, Popular Science had an article about a system that corrected for
    this
    problem. Sorry I can't quote when. I believe it used a slip ring in a
    novel way.
     
  5. Rich Grise

    Rich Grise Guest

    Variable-pitch props have been almost routine for quite some time. But if
    you're running a windmill, is it "correct" to call the turbine blades a
    "prop?"

    Thanks,
    Rich
     
  6. Peter Lawton

    Peter Lawton Guest

    And being equally pedantic, if they aren't milling then are they mills?

    Peter
     
  7. Rich Grise

    Rich Grise Guest

    I think that might depend on what your definition of "mill" is:
    -----------------------
    Webster's Revised Unabridged Dictionary (1913) [web1913]

    Mill \Mill\ (m[i^]l), n. [L. mille a thousand. Cf. Mile.]
    A money of account of the United States, having the value of
    the tenth of a cent, or the thousandth of a dollar.

    Mill \Mill\, n. [OE. mille, melle, mulle, milne, AS. myln,
    mylen; akin to D. molen, G. m["u]hle, OHG. mul[=i], mul[=i]n,
    Icel. mylna; all prob. from L. molina, fr. mola millstone;
    prop., that which grinds, akin to molere to grind, Goth.
    malan, G. mahlen, and to E. meal. [root]108. See Meal flour,
    and cf. Moline.]
    1. A machine for grinding or comminuting any substance, as
    grain, by rubbing and crushing it between two hard, rough,
    or intented surfaces; as, a gristmill, a coffee mill; a
    bone mill.

    2. A machine used for expelling the juice, sap, etc., from
    vegetable tissues by pressure, or by pressure in
    combination with a grinding, or cutting process; as, a
    cider mill; a cane mill.

    3. A machine for grinding and polishing; as, a lapidary mill.

    4. A common name for various machines which produce a
    manufactured product, or change the form of a raw material
    by the continuous repetition of some simple action; as, a
    sawmill; a stamping mill, etc.

    5. A building or collection of buildings with machinery by
    which the processes of manufacturing are carried on; as, a
    cotton mill; a powder mill; a rolling mill.

    6. (Die Sinking) A hardened steel roller having a design in
    relief, used for imprinting a reversed copy of the design
    in a softer metal, as copper.

    7. (Mining)
    (a) An excavation in rock, transverse to the workings,
    from which material for filling is obtained.
    (b) A passage underground through which ore is shot.

    8. A milling cutter. See Illust. under Milling.

    9. A pugilistic. [Cant] --R. D. Blackmore.

    Edge mill, Flint mill, etc. See under Edge, Flint,
    etc.

    Mill bar (Iron Works), a rough bar rolled or drawn directly
    from a bloom or puddle bar for conversion into merchant
    iron in the mill.

    Mill cinder, slag from a puddling furnace.

    Mill head, the head of water employed to turn the wheel of
    a mill.

    Mill pick, a pick for dressing millstones.

    Mill pond, a pond that supplies the water for a mill.

    Mill race, the canal in which water is conveyed to a mill
    wheel, or the current of water which drives the wheel.

    Mill tail, the water which flows from a mill wheel after
    turning it, or the channel in which the water flows.

    Mill tooth, a grinder or molar tooth.

    Mill wheel, the water wheel that drives the machinery of a
    mill.

    Roller mill, a mill in which flour or meal is made by
    crushing grain between rollers.

    Stamp mill (Mining), a mill in which ore is crushed by
    stamps.

    To go through the mill, to experience the suffering or
    discipline necessary to bring one to a certain degree of
    knowledge or skill, or to a certain mental state.

    Mill \Mill\, v. t. [imp. & p. p. Milled; p. pr. & vb. n.
    Milling.] [See Mill, n., and cf. Muller.]
    1. To reduce to fine particles, or to small pieces, in a
    mill; to grind; to comminute.

    2. To shape, finish, or transform by passing through a
    machine; specifically, to shape or dress, as metal, by
    means of a rotary cutter.

    3. To make a raised border around the edges of, or to cut
    fine grooves or indentations across the edges of, as of a
    coin, or a screw head; also, to stamp in a coining press;
    to coin.

    4. To pass through a fulling mill; to full, as cloth.

    5. To beat with the fists. [Cant] --Thackeray.

    6. To roll into bars, as steel.

    To mill chocolate, to make it frothy, as by churning.

    Mill \Mill\, v. i. (Zo["o]l.)
    To swim under water; -- said of air-breathing creatures.

    Mill \Mill\, v. i.
    1. To undergo hulling, as maize.

    2. To move in a circle, as cattle upon a plain.

    The deer and the pig and the nilghar were milling
    round and round in a circle of eight or ten miles
    radius. --Kipling.

    3. To swim suddenly in a new direction; -- said of whales.

    4. To take part in a mill; to box. [Cant]

    Mill \Mill\, n.
    1. Short for Treadmill.

    2. The raised or ridged edge or surface made in milling
    anything, as a coin or screw.

    Mill \Mill\, v. t.
    1. (Mining) To fill (a winze or interior incline) with broken
    ore, to be drawn out at the bottom.

    2. To cause to mill, or circle round, as cattle.

    WordNet (r) 2.0 [wn]

    mill
    n 1: a plant consisting of buildings with facilities for
    manufacturing [syn: factory, manufacturing plant, manufactory]
    2: Scottish philosopher who expounded Bentham's utilitarianism;
    father of John Stuart Mill (1773-1836) [syn: James Mill]
    3: English philosopher and economist remembered for his
    interpretations of empiricism and utilitarianism
    (1806-1873) [syn: John Mill, John Stuart Mill]
    4: machine that processes materials by grinding or crushing
    [syn: grinder]
    5: the act of grinding to a powder or dust [syn: grind, pulverization,
    pulverisation]
    v 1: move about in a confused manner [syn: mill about, mill
    around]
    2: grind with a mill; "mill grain"
    3: produce a ridge around the edge of; "mill a coin"
    4: roll out (metal) with a rolling machine

    The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]

    mill

    Arithmetic and Logic Unit

    Easton's 1897 Bible Dictionary [easton]

    Mill
    for grinding corn, mentioned as used in the time of Abraham
    (Gen. 18:6). That used by the Hebrews consisted of two circular
    stones, each 2 feet in diameter and half a foot thick, the lower
    of which was called the "nether millstone" (Job 41:24) and the
    upper the "rider." The upper stone was turned round by a stick
    fixed in it as a handle. There were then no public mills, and
    thus each family required to be provided with a hand-mill. The
    corn was ground daily, generally by the women of the house (Isa.
    47:1, 2; Matt. 24:41). It was with the upper stone of a
    hand-mill that "a certain woman" at Thebez broke Abimelech's
    skull (Judg. 9:53, "a piece of a millstone;" literally, "a
    millstone rider", i.e., the "runner," the stone which revolves.
    Comp. 2 Sam. 11:21). Millstones could not be pledged (Deut.
    24:6), as they were necessary in every family.
    ------------------

    ;-)

    Cheers!
    Rich
     
  8. It depends on what the definition of "is" is. I looked it up. It said,
    "see 'be'". "see be"? Seabee? CB? C.B.DeMille? See, be de Mill?

    Eerie!

    ;^j
    Rich
     
  9. Peter Lawton

    Peter Lawton Guest

    You are going round in a circle, finding wheels within wheels.
    As is well known, everything returns to milling eventually if you mull over
    it long enough.
    Even our word for distance comes (possibly) from the statutory Roman minimum
    distance
    between mills (so they wouldn't steal each other's wind). And a 'League' of
    course was three mills.
    The last mill was always the longest because it had to take the least windy
    position and so needed
    bigger sails.

    Peter
     
  10. Active8

    Active8 Guest

    We've got some serious (albeit interesting) wind going on in this
    sub-thread :)
     
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