Patent ID: 7275003
Filing Date: 2007-09-25
Classification: H02P

Abstract:
1. A method of harmonic diagnosis for electric equipment to determine an abnormality of an electric motor or inverter from a current harmonic flowing to said electric motor and inverter that form electric equipment, comprising: comparing an index value, which is obtained by dividing a relative harmonic content of each order of current harmonics by total harmonic distortion of the current harmonics up to a predetermined order, with a criteria value, which is obtained by multiplying a harmonic function of each order found through calculation from the relative harmonic content of each order, wherein the degrees of deterioration of said electric motor and inverter are distinguished from each other by weighting said criteria value, and a deteriorated part is determined from a specific harmonic order of said current harmonics, used to prevent abnormality of the electric motor or inverter.