The method of multiple reference frames applied to the diagnosis of stator faults in three-phase induction motors

This paper exploits the use of the multiple reference frames theory for the diagnosis of stator faults in three-phase induction motors. A simplified mathematical model in d-q-0 axes, able to simulate the behavior of the motor in the presence of stator faults, allowed the development of some analytical relations between the d-q-0 current components in different reference frames. The use of the stationary reference frame, clockwise and counterclockwise synchronous reference frames, allows the extraction and manipulation of the information contained in the three motor supply currents in a way that the effects introduced by the fault are isolated and measured. A severity factor is defined, and simulation and experimental results demonstrate its high independence in relation to the working conditions of the motor such as the load level and unbalances in the voltage supply system.