MOTOR DIAGNOSIS DEVICE

[Problem to be Solved] Provided is an electric motor diagnosis device capable of diagnosing the presence or absence of abnormality of an electric motor by means of detecting sideband frequencies appearing in peak states on both sides in vicinity to a power source frequency, even in the motor whose load torque varies.[Means for Solving the Problem] In the device, an electric current of an electric motor 5 is detected by an electric current detector 4, and inputted from an electric current input unit 10; a smoothing process is carried out on a plurality of charges of analytical results of power spectra obtained by a logic calculation unit 11 by performing frequency analysis on an electric current waveform when the electric current is stable; from analytical results of power spectra on which the smoothing process is carried out, sideband frequencies are detected, and also the presence or absence of abnormality of the motor 5 is determined by calculating a difference value between a power spectrum's peak of a power source frequency of the motor 5 and a power spectrum's peak in a rotational frequency band thereof; and a warning is outputted from a warning output unit 12 when determining abnormality being caused.