Study performance of a three-phase induction motor under unbalanced conditions

Abstract

The aim of this research is to investigate and illustrate the impact of unbalanced supply voltages on the operation and performance of a three-phase induction motor. Three-phase supply voltages, unlike single-phase supply voltages, can become unbalanced in a variety of ways, whereas a balanced situation maintains consistent voltage magnitude and angles in all three phases, albeit a truly balanced condition is impossible to achieve in practice. Imbalance situations might arise on several ranges and it can be harmful to the motor. A 3 phase induction machine is designed to work under balanced conditions, but under unbalanced situations, it can experience a variety of complex changes in its mechanical and electrical variables. This study analyzes distinct symmetrical and asymmetrical settings in terms of mechanical and electrical responses to better understand the magnitude of such changes. Rotor and stator currents, electromechanical torque, and rotor speed are among the reactions. To investigate these responses and motor behavior under various unbalanced conditions, a simulation model of a three-phase induction machine is employed, along with various software-generated subsystems. The motor's final throughput is calculated using torque-speed characteristics and derating factor curves for various unbalanced voltage circumstances. A common view is that a complete breakdown of a phase is far more harmful to motor function than a percentage increase or decrease in voltage level or phase. Furthermore, a change in the phase angle of the voltage has indeed been observed to cause more changes in the responses than a change in the voltage magnitude. The quantifiable correlation between voltage imbalance and the resultant mechanical and electrical outputs will aid in the design of proper voltage imbalance prevention. This research would also aid in the development of derating factors for motors running in various imbalanced circumstances.