An improved method for the detection of phase failure faults in poly phase Induction machines

This paper presents an improved method for the detection of phase failure faults in poly phase induction machines. Phase failure occurs when one of the three phases of the supply goes down during the running of motor. Poly phase induction motors continue to operate in this condition but under some severe operating conditions and eventually resulting in performance degradation and permanent burnouts. Detection of phase failure by voltage measurement is not useful in case of poly phase machines and it is not possible even by current monitoring if the machine is installed in a system with a mixture of 1-phase and three-phase loads. The proposed method relies on the continuous measurement the phase difference between the terminal voltages of the machine. Further it presents an improvement in other existing methods which are based on stator current monitoring. The proposed method has been simulated using MatLab/Simulink. The simulated results show the reliability and usefulness of the proposed method.