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 SA, SB 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 SL, are detected from the frequency analysis; and a third step in which the absolute value of the difference between the power frequency fline and the peak position frequency of either of the sidebands SA, SB is set as the actual rotation frequency fr of the three-phase induction motor 12, wherein the actual rotation frequency fr is set as a first characteristic feature quantity.