Dynamic investigation of Georges phenomenon related to three-phase wound-rotor induction motor

Abstract

Abstract The aim of this paper is to analyze the performance of a three-phase wound-rotor induction motor (WRIM) under rotor windings asymmetry. The dynamic performance of the WRIM under healthy and rotor windings asymmetry with one-open-phase fault conditions is analyzed using a dynamic model in the ABC frame. Under opening one phase of the rotor windings, the WRIM suffers from operation at a speed near to the half of its synchronous speed, which is known as the Georges phenomenon. The behavior of the WRIM is simulated and investigated experimentally under faulty conditions for four different possible connections of rotor windings. The stator and rotor currents are analyzed using fast Fourier transformation technique to identify the fault signatures. The results prove that under opening one phase of the rotor windings the WRIM suffers from pulsating electromagnetic torque, high oscillatory stator currents and high unbalanced rotor currents. Also the results prove that the performance of the motor under rotor windings asymmetry conditions and the occurrence of Georges phenomenon depend on the type of connection of the rotor windings and fault location. Therefore, the authors suggest a special delta connection for the rotor winding to reduce the effects of this phenomenon. The simulation and experimental results show good agreement and prove the validity of the suggested delta connection.

Keywords

• Wound-rotor induction motor
• Rotor windings asymmetry
• Open-phase fault
• Georges phenomenon