. The principles of physics. ed in A large massor bar of soft ironof the U form, sur-rounded with a coilof insulated wire,and terminating inthe pole pifioes S., forms thefield magnet. Thearmature consists of a single rectangular loop of wire, which is fixed to a hori-zontal axis, and terminates in two rings of metal, a and b,which are fixed to the axle, but insulated from it. When a current passes through the field coils, and the corebecomes magnetized, lines of force will cross and fill the spacebetween the pole pieces of the field magnet. As these linesare cut by the horizonta
. The principles of physics. ed in A large massor bar of soft ironof the U form, sur-rounded with a coilof insulated wire,and terminating inthe pole pifioes S., forms thefield magnet. Thearmature consists of a single rectangular loop of wire, which is fixed to a hori-zontal axis, and terminates in two rings of metal, a and b,which are fixed to the axle, but insulated from it. When a current passes through the field coils, and the corebecomes magnetized, lines of force will cross and fill the spacebetween the pole pieces of the field magnet. As these linesare cut by the horizontal parts of the rotating wire, an generated in these parts, and a current flows in the direc-tion indicated by the arrows. Apply the preceding rule for determining the direction ofthe current by letting the forefinger of the right hand takethe direction of the magnetic lines of force, the thumb thedirection of motion at right angles to the lines of force, andthe middle finger the direction of the induced current. The. Fig. 451. 562 ETHEE, DYNAMICS. end portions of the loop do not cut lines of force, and there-fore no is generated in them, and they are dead wire,— simply serving as conductors to complete the circuit. Ametallic or carbon brush, m, touches and carries off the cur-rent from the lower horizontal segment of the rectangularcoil. This current flows through the external resistance, E,and completes the circuit through the brush, n, to the ring, b,and the upper half of the loop. The current will continue toflow in this direction while the loop moves through one halfof a revolution. Since the lines of force are cut in the oppo-site direction in the next half revolution, the current will bereversed in the armature wire and also through the externalcircuit. Thus with each half revolution of the armature areversal of the current takes place. This, then, would becalled an alternating currenf dynamo. 628. The commutator. — The alternating current is notadapte
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysics, bookyear1895
