. Hawkins electrical guide. Questions, answers & illustrations; a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications; a practical treatise. ALTERNATORS 1,165 same as the normal frequency. In both cases the eddy currents whichare set up, produce a marked increase in the load losses, and thus tendto give the machine a higher temperature rise on single phase loading. Designers continue to be singularly heedless of these single phasereactions, resulting in many cases of unsatisfactory single phasea
. Hawkins electrical guide. Questions, answers & illustrations; a progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications; a practical treatise. ALTERNATORS 1,165 same as the normal frequency. In both cases the eddy currents whichare set up, produce a marked increase in the load losses, and thus tendto give the machine a higher temperature rise on single phase loading. Designers continue to be singularly heedless of these single phasereactions, resulting in many cases of unsatisfactory single phasealternators. Single phase reactions distort the wave form of themachine. Three Phase Reactions.—The action of the three phase currentsin an alternator is to produce a resultant field which is practically uni-form, and which revolves in synchronism with the field system. Theresultant three phase reaction, because of its uniformity, produces no. 1,426.—Diagram showing lateral field between adjacent poles. great increase in the load losses of the machine, the small additionallosses which are present being due to windings not being placed actuallyin space at 120°, and to the local leakage in the teeth. Magnetic Leakage.—In the design of alternators the dropof voltage on an inductive load is mainly dependent upon themagnetic leakages, primary and secondary. They increase withthe load, and, what is of more importance, they increase withthe fall of the power factor of the circuit on which they may beworking. This is one reason why certain types of alternator, HAWKINS ELECTRICITY though satisfactory on a lighting circuit, have proved them-selves unsatisfactory when applied to a load consisting chieflyof motors. The designer must know the various causes which contributeto leakage and make proper allowance. In general, to keep the leakage small, the pole cores shouldbe short, and of minimum surface, the pole shoes should n
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