Per-unit impedances of synchronous machines

THE ANALYSIS of synchronous machinery is dependent upon a correct and complete knowledge of the machine impedances. The progress of synchronous-machine analysis has been characterized by the recognition of an increasing number of rotor circuits and by an accompanying need for accurate numerical data on the impedances of these additional rotor circuits. The modern equivalent-circuit method of analysis demands an almost limitless array of impedances involving not only mutual reactances but mutual resistances as well. As the application engineer, confronted by more complex application problems, has created more complete equivalent circuits, he has demanded of the design engineer accurate numerical data on the impedances of additional rotor circuits previously ignored. The design engineer himself has been confronted with more complex design problems which have made him directly cognizant of the need for more complete impedance data.