Abnormality diagnostic device for power transmission mechanism and abnormality diagnostic method for power transmission mechanism

A power transmission mechanism abnormality diagnostic method for detecting abnormality of a power transmission mechanism which transmits power from an electric motor to a mechanical facility as a load, the power transmission mechanism abnormality diagnostic method comprising:

• a first step of measuring current flowing through the electric motor;
• a second step of transmitting a value of the current to a monitoring diagnosis unit;
• a third step of performing frequency analysis of the current;
• a fourth step of detecting outstanding spectrum peaks from a drive current spectral waveform obtained in the second step;
• a fifth step of detecting, among the spectrum peaks detected in the fourth step, a plurality of spectrum peaks that are located at equal intervals and have signal intensities equal to or greater than a threshold value, and determining the plurality of spectrum peaks as power transmission mechanism frequency bands that occur in accordance with a rotation speed of the power transmission mechanism;
• a sixth step of detecting a number of sideband waves other than a power supply frequency, a power transmission mechanism frequency, and a rotation frequency of the electric motor;
• and
• a seventh step of determining whether or not abnormality occurs in the power transmission mechanism, on the basis of the number of the sideband waves.

A power transmission mechanism abnormality diagnostic method for detecting abnormality of power transmission mechanisms which transmit powers from a plurality of electric motors to respective mechanical facilities as loads, the power transmission mechanism abnormality diagnostic method comprising:

• a first step of measuring currents flowing through the electric motors;
• a second step of transmitting values of the currents to a monitoring diagnosis unit;
• a third step of performing frequency analysis of the currents;
• and
• a fourth step of comparing drive current spectral waveforms obtained in the third step, and determining whether or not abnormality occurs in the power transmission mechanism.