Analysis and Modeling of a Synchronous Machine with Structural Asymmetries

Most of the online fault diagnostic results are adversely affected by the supply unbalance and the structural asymmetries of the machine. However, in practice, it is impossible to realize a perfectly symmetrical electric motor fed by a balanced supply. Hence, in this paper, the influence of supply unbalance on the performance of synchronous machine with constructional asymmetries has been discussed. In order to conduct a theoretical study, asymmetries in the stator winding and the field winding of the machine have been considered. The field current signature analysis of the machine model with aforementioned asymmetries, with balanced and unbalanced supply, has been presented. In order to validate the theoretical results, experimental results by analyzing the field current and the voltage induced in a rotor-mounted search-coil of a synchronous machine have also been presented. The results of such a study will be extremely useful in developing unambiguous fault diagnostic tools