Abnormality diagnosing device and abnormality diagnosing method

An abnormality diagnosing device adapted to diagnose a driving abnormality of a single motor that is driven by a plurality of motor driving devices;

• wherein the plurality of motor driving devices calculate a plurality of voltage command values on a basis of a position command or a speed command commanded from a numerical controller, and based on the plurality of calculated voltage command values, voltages are applied to a plurality of windings possessed by the motor, thereby driving the motor;
• the abnormality diagnosing device comprising:
• a command value difference calculating unit adapted to calculate a difference between the plurality of voltage command values calculated by the plurality of motor driving devices;
• and
• a determination unit adapted to determine a presence of an abnormality, in an event that an absolute value of the difference calculated by the command value difference calculating unit exceeds a first threshold value continuously for a predetermined time period.