Abstract: A method and an apparatus are disclosed to detect and isolate faults in a rotary machine having a rotor and at least two stator windings. The method comprises generating an input signal and applying the input signal to a set of stator windings while the rotor is locked at a rotor position, measuring output signals and processing the output signals by Fourier transform to obtain a frequency response, testing the rotary machine at discrete rotor positions to obtain a frequency response function of the rotor position, applying Fourier transform to the frequency response function to obtain a two-dimension frequency response in frequency and spatial frequency domain, comparing the two-dimension frequency response with a reference, determining that there is a fault in the rotary machine if the difference exceeds a threshold number. The apparatus is designed to test a rotary machine using the inventive method.

Abstract: A method and an apparatus are disclosed to detect and isolate faults in a rotary machine having a rotor and at least two stator windings. The method comprises generating an input signal and applying the input signal to a set of stator windings while the rotor is locked at a rotor position, measuring output signals and processing the output signals by Fourier transform to obtain a frequency response, testing the rotary machine at discrete rotor positions to obtain a frequency response function of the rotor position, applying Fourier transform to the frequency response function to obtain a two-dimension frequency response in frequency and spatial frequency domain, comparing the two-dimension frequency response with a reference, determining that there is a fault in the rotary machine if the difference exceeds a threshold number. The apparatus is designed to test a rotary machine using the inventive method.

Abstract: A method and an apparatus are disclosed to detect faults in a rotary machine having a rotor and at least two stator windings. The method comprises generating an input signal and applying the input signal to stator windings while the rotor is locked at a rotor position, measuring output signals from the stator windings and processing all the output signals by Fourier transform to obtain frequency responses of the stator windings, forming derived quantities from all the frequency responses so that the derived quantities are independent of the rotor position, comparing the derived quantities with corresponding reference quantities, determining that there is a fault in the rotary machine if a magnitude or phase difference between the derived quantities and the corresponding reference quantities exceeds a threshold number. The apparatus is designed to test a rotary machine using the inventive method.