Simplified test method for the d-axis transient reactance and time constant

A RELATIVELY simple test method is demonstrated to obtain the transient reactance and time constant of an a-c synchronous generator by an analysis of an oscillogram of the a-c generator field current. This method is applicable in many aircraft electric system studies, such as voltage-regulating stability and voltage rise on sudden removal of load, where only the a-c generator transient effects need to be considered. The influence of the d-c and subtransient armature currents are disregarded because of their comparatively negligible effect on the magnitude of the transient voltage of aircraft generators. Hence, to obtain test values of machine constants for these studies, the more efficient simplified test method may be used.