Voltage supply unbalance effects on the induction motor steady state operating parameters

The aim of this work is to analyze the influence of the level of unbalance on low-power asynchronous motors by indicators such as the unbalance factor defined by American standards, the Crest Factor, and the Total Harmonic Distortion for the stator current. The simulations were carried out in the MATLAB-Simulink software and for input voltage variations were made based on the level of unbalance, undervoltage or overvoltage. The analyzed disturbance level ranges between 180V and 280V counted as the RMS value of the supply voltage modified on one or two phases. The results show that parameters like CF and THD are not directly affected by unbalances. However, the unbalance factor becomes critical even at low levels of unbalance, increasing to completely unacceptable values. These findings suggest that unbalances have harmful effects on the motor, at high disturbance levels the motor suffering severe faults.