Operating characteristics of salient-pole machines

By using the well-known 2-axis theory of Blondel the paper develops on a simple geometrical basis the steady-state characteristics of synchronous salient-pole machines. From these it is shown that appreciable economies can be realized by relating the short-circuit ratio, and thus the synchronous reactance, of an alternator to the stability characteristics required by the load. It is also shown that further economies can be obtained in both alternators and synchronous condensers by designing the excitation system to supply positive and negative field currents. Power-station operation can be simplified and made more reliable by the use of a combined watt- and VAr-meter with a dial based on the power chart evolved in the paper. The common basis underlying the operation of the salient-pole alternator, synchronous motor and condenser, and synchronous reluctance machine is shown by a simple generalized diagram, and the operation of these types of motors is briefly discussed. Equations are evolved for determining machine characteristics with greater accuracy than is given by the geometrical method.