A new sensor has been developed that enables the online condition monitoring of grease in rolling bearings. The sensor is suitable for monitoring critical plant and machinery located in difficult-to-access areas, such as wind turbines and automated assembly lines.

The new grease sensor incorporates an electronic evaluation system, which enables the condition of the grease to be monitored whilst the bearings are operating. The sensor is positioned directly in the rolling bearing immersed in the grease.

This means the schedule for replacing rolling bearing grease can now be planned precisely into maintenance schedules. Any changes in the condition of the grease are detected early, long before any damage can be caused to the bearings.

The grease sensor, which has a diameter of just 5mm and a length of 40mm, is able to detect four parameters of the grease: water content, cloudiness (opacity), wear (thermal or mechanical), and temperature. From these parameters, the sensor’s electronic evaluation system utilises complex software algorithms to generate an analogue signal (4-20mA), which then displays the condition of the grease. By setting alarm thresholds, digital signal outputs can also be generated, indicating whether the grease quality is ‘poor’ or ‘good’.

Schaeffler (UK)
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