Impact of mains power quality on operation characteristics of induction motor

The paper deals with the impact of chosen main power quality indices, such as the voltage distortion, the voltage unbalance and the voltage dip on operation characteristics of an induction motor rated at 4 kW fed from the frequency converter and AC source. In this paper the motor efficiency and motor power factor are analyzed in dependence on the motor load at rated motor frequency and the maximum permitted standard levels of power quality indices. In particular, it is shown that the greatest impact on motor operation characteristics has the voltage dip, and that the motor efficiency decreases approximately linearly with the level of the voltage distortion and the voltage unbalance in the specific range of motor load. To distinguish the energy characteristic differences, we used the standard deviation.