Bearing fault detection capability of frequency response measurement in speed-sensorless operated two-mass-systems

The present paper deals with the capability of bearing fault detection in speed-sensorless operated mechanical multi-mass-systems by frequency response measurement. During the commissioning of multi-inertia-setups, an identification of the mechanical system is mandatory for the correct controller design of the drive. The frequency response calculation is able to serve for this purpose and the result can be utilized as a reference measurement of the undamaged plant for the bearing fault detection. Deviations from this curve at the characteristic bearing fault frequencies allow an early bearing fault diagnosis even in speed-sensorless operation of the drive.