METHOD FOR DETERMINING CHARACTERISTIC FEATURE QUANTITY OF THREE-PHASE INDUCTION MOTOR

摘要

This method, for determining a characteristic feature quantity of a three-phase induction motor required for calculation of a deterioration parameter used in diagnostics of a rotary mechanical system for which the three-phase induction motor is the drive source, involves: a first step for performing frequency analysis of an operation-time current signal of the three-phase induction motor 12; a second step in which the sidebands S_A, S_B present in a frequency region A on the low frequency side and a frequency region B on the high frequency side, said regions being centered on the power frequency spectrum S_L, are detected from the frequency analysis; and a third step in which the absolute value of the difference between the power frequency f_line and the peak position frequency of either of the sidebands S_A, S_B is set as the actual rotation frequency f_r of the three-phase induction motor 12, wherein the actual rotation frequency f_r is set as a first characteristic feature quantity.