ABSTRACT
Balanced three-phase sinusoidal steady-state, is only an ideal, rarely achieved condition for either a motor or a generator. It is useful to consider again the case of steady-state operation of a three-phase, three-wire synchronous machine this time for the general case wherein the three source voltages are arbitrary periodic functions. Since the inductances of a synchronous machine become time invariant only when expressed in the rotor reference frame, it is not practical to transform each of the stator voltages to synchronously rotating frames. In general, regardless of the form of the source voltages, the synchronous machine equations, expressed in a reference frame rotating at any rotor speed are described by Park’s equations. In reality a turbo-generator would never be called upon to accelerate from rest, particularly when excitation is applied. When a synchronous machine is subjected to an unbalanced supply, the resulting currents which flow can result in destructive heating within the machine.
