Effect of unbalanced voltage on operation of induction motors and its detection

Deficiencies like unbalanced voltages in the voltage source could result in problems like excessive losses, over-voltages, mechanical oscillations, and interference with control electronics. Detecting these abnormal conditions in the machine is of great importance in the interaction of the electrical machine and the power grid. In this paper the effect of the unbalanced voltages on the motor performance, have been investigated. Then, monitoring these unhealthy condition using electrical machine parameters is carried out. In this case, motor itself can act as the sensor that detects abnormal conditions. Also this paper investigates the negative effects of unbalanced sinusoidal voltage which always present in the power supply voltage on the performance of induction motor in terms of line currents, power factor and efficiency. According to the test results and analysis, the unbalanced sinusoidal voltage has very negative effects on the motor´s performance.