The Montgomery advertiser., 1901-09-06
The ADVERTISERS
 V HOME STUDY CIRCLE

of the total power of the engine, light isolated sections of shafting can be driven dent heepi to pmachinerv reDairs m eest estra @ work york only one. department at time need be llsEtias stations motors are used Q Srs.e
 smp. er nss such sue generators would need to be Seited
 otoPrs Ds supplied sR S as any of several large generators that might be Tn sisss not exceeding q few horse power motors can be operated on the same circuits that supply tncandescent variable loads canss % local variations yaIl of able to correct Such sizes would demand Eelatveiy large cnrrsnts. and supply at
 ilc i to 2co yolts woalS demand large ser. avoided by providing separate generators for motor circuits, usually supplying 300 to $50 volts. The station managers dream
 and mssors from the hss not been, nor is 1t likely to be, rea1tzed,
 In electrical engineering, as in the other
 s hEa,y r.ts orE aIe ing under predetermined definite condi-
 Bipolsr field magnets are most s,itahle construction would be illustrated by the typical forms of Edison and Thompson Houston manufacture. These require commntator. and sufscient sssaents and insulations intervene to prevent "srcing
 from one brush to the opposite. Larger ments and more subdivisions sn the wind ing can advantageeusly have four or more poles, with a considerable saving in eestrc er motors os shoSM and refinement of construction that augurs well for long and minimum at. tsntien: partisSisriy the A sAaft esarin.gs .', elf-oiling. The upper portion of the pedestal is a reservoir for holding in the bearing and dip into the oil; as the shaft rotates these rings slowly turn around and deliver almost a flood of oil
 Spherical Seat self-oiiing bearings, field magnets are some of the eharacteris- tics; armaturs Is strongly relatively ts the adhered to in larger sizes shiftiha of the neutral point with every change of load and disastrous spar king would De realised. slow aos speed speed and high efseiensy.' ' General proportions for some other motors for stantionary purposes can be obtained sres sG% cuts rs ss esss aoaaonss fgsH rrssss service have demanded rather different lines of construction, and these peculiari- ties will form pert of the suhtect-matter
 As was noted earlier in these papers, the activity Of any prime mover can hs expressed by the product of the speed and efficiency of an armature is proportional to it's counter-eiectre motive lorce. If the field magnet is of constant strength will be proportional to the impressed elec- tromotive force; the tofque will be pro- portianal to the current flowing in the ts reuSreS toIs mae
 tain the field magnetlsm, consider the case when there is no load on the arma. ture; then the speed Is the highest, and applied e. m.. f., but the current is Q minimum. and the product of speed times toraue Is a small aaantity-tust sufficient exterior is concerned no work Is being done: the useful efficiency of the machine is zero. For the other extreme imagine would then be zero. the current 8 maxi mum, but the product would. be. sero, Somewhat between these two limits the ~Ses tSs Srosacs SS c appssS ss would be Q maximum. Jaeobi showed this to be at the particular time when the 9n.Sa,s wsS rsne s,e
 in. f. Under these conditions the ef- fioiency would be 50 per cent, Fer many this lay was sn.e, PressG S as a1 nesn Seat
 return but go per cent of the power sup, piled by the generator: Siemens showed that by reducing the lead oa the motor. and geuerate a hlgheE c, e. ,ul. f,. it's effi- ciency was corresp :ndingiy increased, Al the present time meters gre net dnsignsd ciency, and wires only large enough to thes' Ess'r srmaturs sn SwindIns. With the possi-
 ss ssssDGnd D%mdns @ wS fyeE sEs possSs ssRS5 a
 Iep ieadsd to S tie i"p point of 'nsximuia "a output
 nsa y9sa quickly sySen ASS arss oS Sarre oeeSa esi tolerated for few minutes only, just at starting or In olimtdng short, steep
 grad When sHGh ssoSSS stssSv 6ek spe ShSa tSss hurs.s newer rating Is but one hals as much a1 their railway rating,
 An interestlns tllusotvAtien of the reverv
 cn0n csS of etSed Ss sf tessins n fsefSry Suppose two identical machines. each ef 500 k. " capacity. are awaitina their test ed fuH "A useful us dT load cannot alwsys be pror
 SsHeH; Ss HsesssarS, SSa Instead ef this the sss
 aeNss Nasesser ese os snd os o ss Ssea
 d generator to send cuFFents into the ohsF $ a. meter osor ssSay sSsh sSss s.sttS
 emSsent coming out ef the geneFeteT 10 onerats the motor and the motor would be strong enough to drive tAe geDeESt1r: has such an eftiOtency the uAAvaiaable losses must be supplied by some exterior help, either anothSr motor or a steani engine, The large dynamos could esaily | ba rated at 90 per cent efacieneyl henen l to allow for testing both ht full load. l representIng 1,500 h. D.. only about auo | h. D., ned be supplied. II is rather neysl | beIted to the same eountershaft, or to the | two wheels of a center-crapk engine, eHd | notice that one belt is tight on !ep alla | Fa, snS tight below indeed, the only wRY | t.np indee which machine is heinE. Ariven 1, to Itbe engine and which is helping the
 ppSSoine is 10 determine NR0n Hhteh alde