Patent ID: 9279431
Filing Date: 2016-03-08
CPC Classification: F04D,F05D

Claim Text:
1. A method for detecting rotating stall in a compressor comprising a rotating rotor and a static stator, the rotor and the stator being subject to radial vibration and axial vibration, the method comprising: measuring radial vibration of the rotor relative to the stator and correspondingly generating a vibration measurement signal; calculating a frequency spectrum of the vibration measurement signal; identifying a plurality of frequency bandwidths of the frequency spectrum; neglecting one first frequency bandwidth of the plurality of frequency bandwidths if the rotation frequency of the rotor falls within the first frequency bandwidth; neglecting at least one second frequency bandwidth of the plurality of frequency bandwidths if the rotation frequency of the rotor falls below the second frequency bandwidth; determining the maximum magnitude of the spectrum in each of the non-neglected frequency bandwidths; and carrying out a comparison between each of the determined maximum magnitudes and a predetermined value, wherein rotating stall is considered occurring if at least one of the comparisons shows that the corresponding determined maximum magnitude is greater than the predetermined value.