METHOD AND DEVICE FOR DETECTING DEFECT OF MOVABLE MACHINE PART

摘要

Known are systems or devices wherein the transducer comprises a resonance-frequency-range of 30-40 KHz. Such a system is therefore sensitive for disturbances generated by surrounded elements appearing as 2nd and 3rd harmonics. To overcome these disadvantages the invention introduces a system wherein the transducer (3) mounted on a rolling bearing is connected to an amplifier (4) which first output is connected to a multiplier (5) and its second output connected to an oscillator (6) having a frequency of 455 KHz. The output of oscillator (6) is connected to a low-pass filter (7) of 3 KHz. Consequently the output signals of filter (7) corresponds with a frequency-range of 452-458 KHz. Due to this arrangement 2nd and 3rd harmonic vibrations generated by e.g. running parts outside the bearing cannot appear as disturbances.