LOAD ABNORMALITY DETECTION DEVICE

To provide, even in the case of an electric motor of which load torque varies, a load abnormality detection device that can detect an abnormality in a load driven by the electric motor on the basis of a spectrum peak series of a sideband wave that occurs in a peak shape at both sides in the vicinity of a power supply frequency. In the load abnormality detection device, the current of an electric motor 5 is detected by a current detector 4 and inputted from a current input unit 10. Then, in a logic calculation unit 11, a plurality of power spectrum analysis results each obtained by frequency analysis being performed on the current waveform when the current is stable are subjected to an averaging process. Then, a sideband wave is detected from a power spectrum analysis result obtained through the averaging process, and the presence/absence of an abnormality in a load is determined on the basis of a spectrum peak series. When occurrence of an abnormality is determined, an alarm output unit 21 outputs an alarm.