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Show eAvtoma$ik Simplifkd J s By an Automobile Expert. If ticrc is anj-tfcins not c.ir to jou, asi the automolu'e editor about It. An answer will be published on the completion of the artklea pcrt&ining to each section uuder discussion. fimjk tt All J Fig J L Ji I UmsY 1W r-s LESSON NO. 26. , The Magneto. I In Uivse s stems of icnition wliich we have studied .o far t he current came r"im a luery of some kind. nr. I w:is then converted f:om low t" hish tension ard dtstrthuteJ to the spark plu.s in the ::rln? ofler. The magneto, which we will now take up. a eoirpouiui machine, hinc. primarily, pri-marily, a devic for mak:h; the electric current. b;;t ha insr an ached to it the de ices fr inter, ".ptirc this current, so it ran he co:v cru'u from low to hii;!i tension, and fie o c- tor distrihnt-ins distrihnt-ins it t the siM'' I; pai.ss. Let us seo luiw t'e n'asrneto manufne-taies manufne-taies or makes the clcti ic current. If we h,d a uiairnet n:id were to place a piece ot pa. fi on it. then sprinkle some lion iil.r--:s on this i ait i- and tup the p.; per. then they f.i'.i-s would for:.i t c'oseh e in deiinite liiiivi as shown In Fur. I. This 's a pnef iNh t there are certain ir..-ch'.e lints running from oiu ! voio of the ii:anet to the other pole, i The t'MCt th:U i.it-se lines clau maKe t.'e irvr: riltni'.s take a definite course, or. in other words, neve the llluis, nml the fact that the tiT:ct cm litt ;irea; wrishts. prove th.it these linos h;ve ti ctrtain amount of fon e Kt'.smeers call I them iniimiette hus of forc. Hy placing a rH-o of iron. ra'.leO R I iH-Ie i'iec. on the etui of e:ch vole, ns j shown In Kis. the lines of forn e cm ho ! n'.cle take a definite course, as shown, instead of scattering all About the poles in e ei v dii ect'.on. It Is im accepted theory that electricity ' does rot travel tlirvu-;h the metal of the j wire or conductor, hut on tho outside. and In a sort of spiral, j I could recount to you test upon lest, j proving the va:-.ot.s act ions upon whi.-h the current peneranns machines are built. I hut instead of doinp this 1 am soiuc to ask you to use vour imupinatiou and let me try to pict;:tv tho uction to your n.hul p eyes. Imagine the macnettc lines of force. to ht oxv eedlnt;ly small pieces of rubher bands extending from inle to role. Suppose, Sup-pose, now. wo inserted a coil of wire in tills field of hands as shown and then revo!ve-J the co.l in the direction of the arrow. What would happen Tinder the above circumstances? Why, the rubber Winds ou Id finally sap and whip-l.sh about the wire. Kut the wire cannot hold them iiU. so that many will he squeezed alouu the wire, and so travel along: it. As f.isc s the ma ; netic lines are broken new lines are fortne-J, thus there will be a constant stream flowlni; aloixs the wire, just so loni; as the wire is cuttmi; through the lines. In other words, by nmkiii a wire cut thtvuch the magnetic i lines of force, th.e maynetio lines can be 1 tvndo to U(i vel alon; the wires, or be-j be-j cxvne eleeirie current. i It is on this principle that the rrwisr- neto the lit lie generator v. hlch charges I your storage hattery and the slpantic t machine m the electric power plant are 1 j built. Notice that w-ro "A" is out time through the lines in a downward direction, while "H" is cultinc: upward. Thus the current cur-rent will flow out of "A." say. and into "fct." On the next half revolution "A" and "1!" will have changed pla.-es, and the current will now he traveling into "A" and out at "IV while on the next half revolution it will aam alternate in ! direction. When a current in a wire Is t constantly eh.iuini; the direction of flow, ! as above, wo say It is an alternatlnjc cur-! cur-! rent. Tho magneto Is an alternating current cur-rent machine. Notice that wlien the wire is on the top of its reol at ion it will bo traveling in ihe same direction as the magnetic hues of force and -so will not cut any of them. As it revolves a Utile further it will cut a few In a siven time, the amount of lines cut in a fjivtn time increasing as th" ire approaches the horizontal position, when the maximum number wail j be cut. Naturally, the greater the num-i num-i her of lines cut in a siven time the 'greater will ho the force pressing them I alons; the wire, and so the Kfeater w ill j be the aUa i;e. Note t hat the volt. ice w ill decrease as the w ire travels siUt fui rtv-r, untd It irets to the bottom, when I it wll! be aero, and then it will asaiu iu-1 iu-1 crease, but the rlow will now bo In the j ppsl; direction. 1 As the mas neto is built, the win is ' wrapped around a soft iron core, the coil j of wire and core hems called the rma-j rma-j lure. The armature core has fastened j U ea-'h end a shaft, which runs In ball j hearings, and so holds the armature in place between the pole pieces One of : ht s- sha : t s also is com .cct e 1 to the driving mechanism. The nvu'.r.ets are of hard steel and known as 1 ernianent n'.dnets. These ! mapnet.s w ill he ma-nets until tho ecd 'of tunc, but their strength wil! L.r.idcaily decrease. If by accident t!v current troui a batteiv were to run through the armature arma-ture of the masiti'lo in a eer;Ain litrection, the manetis:n will be ijuickly drawn out of the magnets. Kor this reason sitvil care must be taken in connecting a battery bat-tery sjstem of icnttlon to a magneto a s-tern. s-tern. When the otairneis heco:re weak they can be rema xv. e t iaed. and this nv-iv sometimes he nccessaic ii oider to have I the magneto sive sufficeni current to I yield a sp.uk mi the low rn-'ine speeds. J Kor sliuphcity. and in or.ier to hae as few wares as possible, one end of the armature eotl wire is grounded, while the other is tun out through one of t!ie shafts, which shaft is hollow. The end of this wire terminates in a sort of flat button, as.iinst which a piee 01 carbon, ealied a icUector brc.sh. rulv. and so i collects the curren i mni this wire, a mi j then sends it through another w;re. which is attached ti the brush on the J outside, to the co:l or other pans. K.i;. 4 1 shows the armature In position, and I"!-;. 5 the connection of the wires. I On the front of the tv.aciuno is placed j an- interru'eter ai i distributer, and in a ! later lefoon we wll see just how the car-' car-' rent made by the uti eneto is used to I s:ve the spark, and aiso study some of i the other de ices necessary for its per-j per-j ftot operation. j There a re two classes of magnetos. : namely, the hili Tension and t bo low tension. Wo w dl take them up ser-: ser-: arately. I misht say hei- that ome people do not explain the ma a no to as it v, as ex-S.daine.i ex-S.daine.i above, but base their explanation , on t he fact that the a mat nre .-ore. ;is it revolves In the manneiie fie'd. becomes 1 manrtiaed and demagnetize. i, so that a current Is made to liow m the wire wrapped ahou t it. just as it docs in the induction coil. While t his method is a j:uo.l one. aN,i, prefer to epl lin the action as I have, as vheu we come to the starlit,;-; and lii;htir.u' system we will have a generator to explain. :uui this cannot can-not be explained on the basis of Induction. 1 ilo not believe i:i confesm tnv reaieis but will at a later dale also explain the magneto on the basis or" redaction. We will nexw take up tho low tension magneto. |
