Differential Resonator Method for Incipient Failure Visual Detection of Bearings

The upper and lower limits of detected frequency for differential resonator were obtained by experimental method.The detected upper limit frequency only need to satisfy the sampling theorem while the detected lower one is related to sampling frequency.Under the condition of certain sampling frequency,the lower detecting frequency of differential resonator was about 1/650 of sampling frequency.When the sampling frequency was too high,whether converging to the pole or the polar ring,the phase diagram of differential resonator would present as a pie.Applying this method to the high speed rolling mill fault diagnosis,the phase diagram of the vibration signals changed from pole to polar ring,which implied the running state from normal to incipient fault,thereby providing an effective technology for condition monitoring and fault diagnosis of mechanical equipment.