Analysis of effects of three-phase voltage unbalance on induction motors with emphasis on the angle of the complex voltage unbalance factor

Analysis of the steady-state performance of an induction motor connected to unbalanced three-phase voltages is presented. The index of voltage unbalance used in this paper is the complex voltage unbalance factor (CVUF) that consists of the magnitude and the angle. In addition to formulation and discussion of the motor operating characteristics under voltage unbalance, special emphasis is placed on the effect of the angle of the CVUF on the motor. It is found that the angle of the CVUF is also an important factor that merits particular attention in analyzing voltage unbalance issues.