. A text book of physics, for the use of students of science and engineering . ately excited by means of a continuous current. In small machines this current ipplied by a battery, bu1 in large machines a separate direct- Lxxvrr ALTERNATORS 1001 /yxternal^/ Circuit current dynamo is used for producing the field current. The regu-lation of the alternating voltage to secure constancy is performedby altering the resistance inthe field circuit by means of arheostat. The in the coils de-pends only upon the relativemotion of the coils and thefield magnet. In the case given(Fig. 942) the field
. A text book of physics, for the use of students of science and engineering . ately excited by means of a continuous current. In small machines this current ipplied by a battery, bu1 in large machines a separate direct- Lxxvrr ALTERNATORS 1001 /yxternal^/ Circuit current dynamo is used for producing the field current. The regu-lation of the alternating voltage to secure constancy is performedby altering the resistance inthe field circuit by means of arheostat. The in the coils de-pends only upon the relativemotion of the coils and thefield magnet. In the case given(Fig. 942) the field magnetsare fixed, and the coils rotatein the direction of the machines, however, aredesigned so that the coils arefixed and the field magnetsrotate. For the in theabove case to remain un-changed, the magnets wouldhave to rotate in a direction opposite to that indicated by thearrow. Whichever part is fixed is called the stator. The rotatingpart is called the rotor. As was seen on p. 992, the ring form of armature is wasteful in copper, hence it is desirable. fig. -Rotor connections for a six-polealternator. to arrange the conductorsupon the outside only ofthe iron core. In Fig. 943an arrangement of thirty-sixconductors round the surfaceof the rotor is shown. Theseare supposed to be connectedat the front as shown bythe thick lines and at theback by the dotted are three pairs of polesin the stator. It will beseen that all the conductorsof the rotor are in series andthat they are grouped into sets in such a way that the inthe sets at any one instant is the same, but in passing from one
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectphysics
