Journal of the Association of Engineering Societies . must be of such magnitude andphase position that it will overcome (1) the , Oe^ induced bythe revolving field, (2) the drop in voltage due to resistance ofprimary winding, Orx, and (3) the induced by leakage flux,Oxj. It is, therefore, equal to OE0 in the figure, and has the phaseposition there shown, the construction being obvious. In this figure, 6t is the angle by which the primary currentlags behind the impressed , and the cosine of this angle is theso-called power factor. In order to have a high-power factor, therefo
Journal of the Association of Engineering Societies . must be of such magnitude andphase position that it will overcome (1) the , Oe^ induced bythe revolving field, (2) the drop in voltage due to resistance ofprimary winding, Orx, and (3) the induced by leakage flux,Oxj. It is, therefore, equal to OE0 in the figure, and has the phaseposition there shown, the construction being obvious. In this figure, 6t is the angle by which the primary currentlags behind the impressed , and the cosine of this angle is theso-called power factor. In order to have a high-power factor, therefore, 9X must besmall. To keep 9X as small as possible means a reduction of 02 andXx to a minimum, or, in other words, a reduction of magnetic leak- THE HEYLAND INDUCTION MOTOR. 69 age, the latter being effected by making the air-gap as small asmechanical considerations will permit. If we confine our attention to a motor in which magnetic leak-age and ohmic resistance of primary are negligibly small, thediagram becomes much simplified, as in Fig. Here, Oi2 coincides with Oe2 in phase, and Orx and Oxx assumption is also made that OM is in phase with 0, which isvery closely approximated in reality. The useful power delivered by the motor is, in watts, the prod-uct of OE0 by Oi\, the latter being the component of Oia in phasewith OE0; the other component of current ijiu or wattless current,represents no power, hut it requires just as much copper sectionper ampere as the useful current; and, in addition, it has a bad effectupon the voltage regulation of the system supplying the is obvious that if i^, can he eliminated, the angle &x will becomezero, its cosine, and, therefore, the power factor will become unity,and the characteristics of the system will be improved. This is theprincipal object of the invention of Mr. Heyland, now to be ex-plained. The heavy lines of Fig. 7 are a reproduction of part of Fig. B, is to become zero, i. e., Oi, shifted to Oi\
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectenginee, bookyear1881
