ABNORMALITY DIAGNOSTIC METHOD FOR DRIVING SYSTEM OF MACHINE DEVICE

PROBLEM TO BE SOLVED: To monitor, and predict or forecast abnormality macroscopically in its early stage by monitoring the waveform of the primary-side composite electric power of supplied electric power. SOLUTION: An electric power system has servomotors 3 (x axis 3x, y axis 3y, and z axis 3z), an axis disconnection unit 23, a servoamplifier 20, a DC power unit (AC/DC converter) 24, an electromagnetic on/off relay(MCCR) 25, and a voltage converting transformer 26; and the transformer 26 corresponds to a subunit controller 22 and the secondary side branched from the transformer 26 corresponds to a unit controller 21. To measure electric power waveforms, electric power waveforms of (1) the servomotor 3 itself, (2) the axis disconnection unit 23, (3) DC power unit 25, (4) unit controller 21, and (5) subunit controller 22 are multiplied by N and measured, and a reference waveform is set in consideration of variance by using a statistical method. Then the measured waveforms are relatively compared with the reference waveform and then waveforms of high order are put together to take a macroscopic diagnosis.