Versatile condition monitoring of wind turbine rotor bearings reduces operating costs

How can typical rolling bearing damage in wind turbines, particularly in wind turbine rotor bearing supports, be identified early and even prevented altogether? Schaeffler has a solution to this complex challenge: a combination of sensors that are capable of monitoring the critical influencing variables for this type of damage.

Real time operating data offers huge potential for improving drive trains’ rolling bearing supports and the system as a whole, as well as for optimising wind turbine operation. Evaluating and interpreting this gathered data enables safety factors to be more accurately defined and adapted for new developments. In collaboration with pilot customers, Schaeffler is also developing sensor concepts for recording variables that influence bearing damage and which have not been monitored before.

In the case of Schaeffler’s flanged rotor bearing, for example, the sensor combination used comprises of established temperature and vibration sensors, together with the Schaeffler GreaseCheck grease sensor and the new Schaeffler LoadSense Pin, and an equally new roller set sliding distance sensor.

Schaeffler GreaseCheck grease sensor

The Schaeffler GreaseCheck is an optical sensor system that allows changes in the condition of the grease to be detected early. The sensor head is just 5mm wide and records three parameters: turbidity, water content, and grease temperature.

Schaeffler LoadSense Pin

In the case of pre-assembled rotor bearing systems that are flange-mounted to the adjacent construction, the preload of the screw connections that are used partially determines the bearing’s load distribution and so has a direct effect on its performance capability and operating life. To monitor this screw preload, Schaeffler has developed the LoadSense Pin, a new sensor based on the company’s Sensotect thin-layer sensor technology, and uses the measurement method employed by strain gauges.

Roller set sliding distance sensor

This inductive sensor records the number of times that a rolling element passes the sensor head during a fixed number of rotor shaft rotations. The rolling motion of the contact partners in the bearing always means sliding movements – which are small when the design is correct.