Influence of voltage unbalance in energy consumption of three-phase induction motors in industrial plants in Brazil

In this paper are analyzed the losts on energy and the financial costs due to unbalanced voltages on the operating of three-phase induction motors, installed in four industrial plants in Brazil. Besides that, this paper aims to determinate the efficiency reduction of three-phase induction motors operating with different configurations and levels of unbalanced voltages. The results show that unbalanced voltages combined with undervoltages are the most significantly factors on the motor efficiency reduction. Furthermore, measurements performed on the motors installed on the analyzed plants pointed a line voltage unbalance rate maximum of 1,2%, which represents circa 0,2% of efficiency reduction