Advantages of Broadband Ultrasonic Sensor Technology for Low-Speed Bearings

Christian Probst, Application Engineer, SONOTEC


In the field of condition monitoring of rotating machinery or other equipment and processes, both vibration analysis and ultrasonic testing play a key role. While ultrasound is used as a technology for early failure detection in rolling bearings, vibration is normally applied for the overall machinery condition inspection and root cause analysis. In practice, both methods are often used simultaneously. Measurements are usually taken at the same measuring points on the asset.

SONOTEC´s new transducer principle enables measurement of the range from ultrasound to high frequency structure-borne sound and even down to the range of acceleration with one sensor. In the presentation, this transducer principle is explained in detail with the focus on the technology and the unique characteristics of piezocomposites as well as requirements on the calibration for this type of sensor. Based on the frequency responses, accelerometers and conventional ultrasonic sensors are compared with the new broadband ultrasonic sensor.

Furthermore, the practical use of the sensor concept based on field measurements of rolling bearings is demonstrated. A slow-running rolling bearing is used to describe how damage detection is carried out using the broadband measurement technique. In addition, the extended analysis of the ultrasonic data is described. This makes it possible to use the ultrasonic data to identify the fault pattern and thus the possible cause.


Christian Probst is a Graduate Engineer in Mechatronics and has been working at SONOTEC GmbH since 2006. Career highlights include technology development and implementation for the production of piezocomposites. He also has several years of experience in probe and sensor development for the field of non-destructive testing; broadband probes, multi-element/phased array probes, air-ultrasonic probes. Since 2013, he has been a development and application engineer in the field of preventive maintenance with a current focus on condition monitoring to highlight the advantages of broadband ultrasonic measurement technology. Christian is a Certified ISO CAT II Vibration Analyst by Vibration Institute.