Performance analysis of a reluctance synchronous motor under abnormal operating condition

In recent years, the application of reluctance synchronous motors (RSM) to AC drives has been gaining importance. The RSM with damper bars not only features the advantages of the synchronous motor and the induction motor but also eliminates the disadvantages of these motors. In this paper, the performance of the motor under abnormal operating conditions has been analyzed and compared with its performance under healthy conditions. Initially, a very common type of abnormal condition of any motor i.e., stator voltage unbalance, has been considered for this study. Motor current signature analysis (MCSA) has been used to analyze the performance of the motor under such abnormality. The different spectral lines that are visible in the line current due to supply voltage unbalance have been discussed in detailed. Such analysis is helpful in understanding and identifying stator inter-turn faults. For the present paper, a 460 V, 1.5 hp, 1800 rpm, 4-pole RSM with 36 stator slots and having 24 damper bars with continuous end ring construction has been considered. A detailed modeling of the motor, including individual damper bars and the non-uniform air-gap, has been carried out using a modified winding function approach (MWFA).