. A text-book of electrical engineering;. es, the only moving part consisting of masses ofiron. These masses of iron conduct the magnetic flux across the gap, firstat one point and the next moment at another. The flux through any coilon the armature is continually changing and thus inducing alternatingelectromotive forces in the coil. Machines of this type are specially suitablefor running at high peripheral speeds. A portion of an inductor generatorby the of BerUn is shown in Fig. 292. There are two armatures,A and B, built up of sheet iron, and secured by the frame C which acts asthe
. A text-book of electrical engineering;. es, the only moving part consisting of masses ofiron. These masses of iron conduct the magnetic flux across the gap, firstat one point and the next moment at another. The flux through any coilon the armature is continually changing and thus inducing alternatingelectromotive forces in the coil. Machines of this type are specially suitablefor running at high peripheral speeds. A portion of an inductor generatorby the of BerUn is shown in Fig. 292. There are two armatures,A and B, built up of sheet iron, and secured by the frame C which acts asthe magnetic yoke. At the bottom of the annular space thus formed, themagnetising coil F is wound. On the left is shown the flywheel which carriesa number of iron blocks, G. These blocks offer a path of low reluctance tothe lines of force, which consequently pass, for the most part, through thoseparts of the armature between which the blocks are momentarily magnetic flux practically rotates with the iron blocks, which are there-. Fig. 292 fore equivalent to rotating electromagnets. The armature coils mustnaturally span a distance equal to half the pitch of the blocks. Were magnetic leakage entirely absent, the armature wires in the neutralzone, between the blocks, would be entirely inactive. As the result ofleakage, however, each coil has opposing electromotive forces induced in itstwo sides. If the flux passing across a block is Oj, while the leakage flux,that is, the flux which crosses between two blocks, is O;, then the isproportional to O,, — Oj. When we take into account that the flux does notreverse, but simply varies between zero and maximum, it is evident that,for O in equation (143) on page 296, we must put 0 = ^-^ (139). The great leakage in this type of machine caused it to be given up infavour of the alternate pole type. The chief disadvantage is not so much theadditional ampere-turns required to drive the larger flux through the yokeas the he
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Keywords: ., bookcentury1900, bookdecade1920, bookidcu3192400440, bookyear1920
