Cyber Times International Journal of Technology & Management

In a three-phase system, unbalance voltage introduce when the magnitudes of phase voltages and the difference in phase angles deviates from the balanced conditions. Unbalanced voltage factor have own importance when we are studying the impact of unbalance voltage on the behavior of three-phase induction machines. Problems like over & under voltages, oscillations, high losses and disturbance in phase angle are the key problem of unbalance voltage factor. Searching these abnormal conditions in the machine has major importance in the electrical machine. In this paper a real load test to calculate the deviation of the balance and unbalanced voltages on the motor performance, is observed, including unbalance voltage factor, the positive-sequence voltage, which is  required in the performance of the motor and how the negative-sequence voltage deteriorates the performance of the machine are shown. At last, it is shown that regulations, temperature rise curves and a motor’s derating factor are based on not only a voltage unbalance factor, but it is also depends on the magnitude of the positive-sequence voltage. In this paper the deviation of the balance and
unbalanced voltages on the motor performance; is observed and calculated. It is also shown how variation of positive sequence, negative sequence, rotor and stator current, speed, electromagnetic torque changes with deviation in voltages and its phase angles.