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Show An idea of tho extent in which electricity Is being used In of tho products ThrouperlodoMow prices """fiSBBBSHIK agriculture may be gained from a description of a 300-ncro ntii uch a tlmo as tho advance in tho FOR 773L' PJOTDJ? electrically operated farm on Long Island. This farm, a portion market enables him to soli at tho highest ''"ivrx of which Is salt marsh land not cultivated, was for venrs al. -,.. lowed to grow wild. It was about three years ago that tho presont owner, n Now Yorker, purchased tho property and proceeded pro-ceeded to farm It along modern lines. The first thing tho now owner did was to who tho houso and barns for olectrlcity for light and power. One hundred and sixty electric Incandescent lamps woro Installed about the premises. prem-ises. All tho machines about tho barns wore old, but wero easily cleaned up, and by supplying n few missing parts woro arranged for bolt drive from a countershaft. Tho feed cutter, root cutter, fodder cutter, fanning mill, grlndstbne, circular saw, corn shellor, a Binall drill press and a horso clipper woro grouped so as to bo driven by ono threq-horso-powor motor. Tho fact that no two of tho largo machines woro needed at the samo tlmo mado it possible to uso such a small motor. It cost $3,50Q to install tho privato plant consisting of a, ten-horso-powor gas cnglno driving a live kw. generator. Hut tho yearly cost figured as low as $GD0 less than two-Jhlrds of what tho Qwnor must havo paid to rent electrical power'. That $070 was mado up of, first, Interest on investment nnd depreciation deprecia-tion of plant at 12 pqr cent., $420; and, second, of running expenses ex-penses for fuel, lubricating oil and minor repairs, $250. Thero was no coBt for labor, because the plant required no expert attention at-tention nftor tho dally starting of engine and generator. Ono could do a full day's work und glvo tho electric hired man, between be-tween times, nil tho attention requisite. Tho powor plant was Installed In uu utilised one-story carriage car-riage shod, located at tho westerly end of tho L formed by tho Ilnkod group of farm buildings. That was about 250 feet from tho building containing tho farm machinery and tho creamery, but it pormlttod of utilization of a structuro otherwise (dlo. It was found to bo most economical to Install a storage battery bat-tery to provido a continuous supply of current so the engine ne,od not run all tho tlmo,, or in case anything happened to tho plant. Tho now farmer turned looso this current on a churn, electrically electri-cally driven, and mado It grind out, regularly every day, from 10 to 12 pounds of butter Insldo of IS minutes. A serious mistake was mado by erecting an I8,6o0galion or tnnk, with a wind-mill j whon for $200 a ono-horse powor 'c pump could havo boon Installed which would havo been rates, often double what he would havo received without It. A Binall motor drives tho bottle-washing machine nnd tho pasteurizing pas-teurizing apparatus, nnd, twice n day, it works tho milking ma-chlno ma-chlno on two cows at a time and enables ono man to attend to two or threo machines at once. With a milking machine properly proper-ly carod for as to tho detallB of cleanliness, not a single germ can possibly Invado the milk supply, becauso, from tho time It stnrts from tho udder until It Is nil In tho hermetically sealed pall, not a breath of air comes In contact with It. Tho Incubator and brooder aro also heated by electricity. Electricity sweeps tho floors pneumatically and makes light of that weekly back-breaking Job with tho broom. It turns tho Interior In-terior of tho fnrmhouso from nn oven at two o'clock of a summer nftornoon Into a cool paradise "by means of tho electric fans', and wnrms tho houso In winter by means of electric radiators. It ' washes tho clothes as well, but a good deal moro mercifully, thnn tho wet wash laundry. It also docs the cooking, Ironing, sowing and most of tho dlsagreeablo tasks of -tho kitchen. To understand tho fundamental principles Involved In tho oporntlon of dynamo-electric machines, consider first two magnetic mag-netic polCB, N and S, of opposite polarity placed near to each other. Uetween tho poles N and S Is n field of magnetic force composed of so-called lines of magnetic force which may bo plctorially Indicated by parallel lines, as is done in tho illustration. illus-tration. If a conductor, for examplo u round copper bar O, Is placed -in the magnotic Hold, with Its axis horizontal and perpendicular per-pendicular to the linos of tho force, and Is raised nnd lowered along tho path C D so as to cut tho lines of force up or Induced In-duced In tho conductor. Tho magnitude cf tho ulectrc-motlvo forco produced In tho conductor depends upon tho rate at which tho lines uro cut. Duo to tho olectro-motlvo force, ono end of tho conductor Is raised In consequonco of which thoro Is a tendency ten-dency for electricity to flow along tho conductor, nnd If its two ends aro electrically connected exterior to tho magnetic Held so as to make a closed circuit, a current will How through tho circuit. If tho gap between tho polos N nnd S wero Infinite in extent in tho direction of C D, and if tho conductor O in its niotlon along this Inllnlto path woro supplied with somo sort of sliding contacts by which current could bo taken to ono end and from tho other end, (ho dovico would possess all the essential yJHBBHHHBHB H. j 1FVtrj flOTQR ftPPUCH TWJ18 .1 Ing up nnd In tho opposite dlreo- vK' tlon as It Is coming down. If tho 'B ends of C aro brought down to tho BE Bhaft A, and, formed Into rings D around It, brushes bearing on theso B rings, it connected "with an externa H circuit, win receive an alternating' K'i current, that Is, ono which flows mkl first In ono direction, and then in Dl the opposlto direction. Machines of H this description aro callod riltcrnat- Hj ors; tho rotating part is called tho JB armature; tho polo pieces TJ nnd S j with the remaining magnotic circuit, ff aro called tho field, and tho rings S iround tbo shaft nro called collector 1 H rings. If the current collected Is to rt flow always In the samo direction in w. m tho circuit which Is oxtornal to the 5 mochlno, somo devlco must 'bo pro- vlded to change automatically the " f ex.tornal circuit. Such n device, is called a commutator. I 'III Thus far in tho dlscussttn, It has been assumed that a ' magnet field was already provided without Inquiring In what ;HJ manner It was provided. Tho manners In which such fields may :''B be provided will now bo described. In the earliest machines, fl and lu somo used even now for mcdlcnl purposes, nnd in tho mM ringing magnet of telephones, tho field. Is provided by a per- ' manent magnet. In nil machines of any considerable size, how- 'Jul over, the ofder form of magnet is replaced by an oloctro- msFI magnet. If a current flows through tho winding in the dircc- $il 1 tlon indicated by tho arrow, magnetic poles will bo produced ilJ at N and S, and a magnetic field will exist botween thorn. Tho fiil parts of tho magnet may differ much In form and arrango- IfjM-nient, IfjM-nient, but a magnotic circuit interlinked or wound with an electric circuit is an ossential field may bo furnished from n B, sourco exterior to the genorntor or motor, or, in the coao m of n direct current dynamo, by the machine Itself, Thero aro Am' two wnys in which tho self-excitation may bo accomplished. It JSi current Is taken from the positive brush and led directly IB! through tho magnct-wlndlng and back to tho negative brush, IB tho mngnet Is in parallel or shunt with tha external circuit, 79' und the machine Is called shunt-wound. In a shunt-wound m, machine only part of tho current generated passes through the magnet-winding. If, however, nil of tho current coming vm from the armature passes through tho field-magnet, and thon mWm goes, to tho external circuit, the machine Is called series 1 3B wound. If both shunt and series windings aro employed, tho amm machine Is defined as compound wound. HI The several parts of dynamo-electrlo machines and tunc- fl! tlons which thoy exerclso have been described, nnd tho at- i fflgl tempt has boen made to elucidate briefly and non-technlcally ; tho principles of tho basis of their operation. An account will IB now bo given of their development, and afterwards, the several Hr types of machines In commercial use will be described. Bfij The prlncipjo of electro-magnetic induction upon which tho ! Hp!' operation of the dyuamo-electrlc machine Is based, was dla- jOi covered by Michael Faraday, in 1831. In his first experiment BE Faraday produced a current In a coll of wlro. by starting or IS1 stopping a current In a neighboring coll; H0 then generated mX, currents In a coll by moving It before the poles .of .a, magnet jfcJL' |
