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

摘要

A method for determining the characteristic feature quantity of a three-phase induction motor which is required to calculate a deterioration parameter used when diagnosing a rotary mechanical system using the three-phase induction motor as a drive source includes a first process of performing frequency analysis of a current signal in operation from a three-phase induction motor () , a second process of detecting, by frequency analysis, sideband waves SA and SB of a power supply frequency spectrum SL as the center which respectively exist in a frequency domain A on the low frequency side and a frequency domain B on the high frequency side, and a third process of setting, as an actual rotation frequency fr of the three-phase induction motor (12) , the absolute value of the difference between a power supply frequency f —line and the peak position frequency of one of the sideband waves SA and SB, thereby setting the actual rotation frequency f r as the first characteristic feature quantity. 27