. Electric railways; a treatise on the modern development of electric traction, including practical instruction in the latest approved methods of electric equipment and operation . ent in tlu> field and armature is constant and themotor has, therefore, a tendency to turn eontinuouslv in ()n(^ direc-tion as lon^ as the alternatin<:;-current power is suj^plied. This bein^ (rue, the (piestion may arise as to why the sin<jle-phase motor was not l)r()u^lit to the front for railway work lon<^ago. ihe answer is that there were certain inherent difficultiesto he (nercome, and the developme
. Electric railways; a treatise on the modern development of electric traction, including practical instruction in the latest approved methods of electric equipment and operation . ent in tlu> field and armature is constant and themotor has, therefore, a tendency to turn eontinuouslv in ()n(^ direc-tion as lon^ as the alternatin<:;-current power is suj^plied. This bein^ (rue, the (piestion may arise as to why the sin<jle-phase motor was not l)r()u^lit to the front for railway work lon<^ago. ihe answer is that there were certain inherent difficultiesto he (nercome, and the development of the single-phase motorhas been simply the removal of these difficulties, rather than thedesign of an entirely new type of macliine. The most serious obstacle to overcome is the sparking at thecommutator, (]uc to the fact that when the terminals of a coil arebridged by a brush, the coil acts like the short circuited secondaryof a transformer of which the field winding constitutes the there is an iron loss due to the alternating magnetic flux throughthe magnetic circuit; wliile another objectionable feature is thecounter E.^ induced in the field Alternating-Current Kailwuj- .Motor Iiclil. In order that it may overcome these difficulties, to some extent,at least, the single-phase motor presents certain modifications fromthe direct-current type, in that it has more field poles, and the entiremagnetic circuit of field frame, cores, and pole pieces, is carefullylaminated. The number of conmiutator segments is also increased,thus reducing the number of armature turns per coil, and thereare special features introduced to prevent sparking, such as com-pensating windings which neutralize the effect of armature dis- THE SIXGLK-PHASE ELECTRIC HAIEWAY U]
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Keywords: ., bookauthoramericanschoolchicago, bookcentury1900, bookdecade1900
