Analogue inductive sensors offer micron accuracy to optimise wind turbines

(See Plus Automation at FoodManufacturing.Live, 15 May 2025, on stand 49)

Along with the trend for wind turbines to increase in size and be positioned in hostile environments on hills or offshore is the use of increasingly complex automation systems to optimise their performance, of which Contrinex inductive sensors, available in the UK from Plus Automation, play a key part.

The high costs of wind turbines make their optimisation increasingly essential to maximise their economic value. The pitch of the turbine blades catching the wind is the primary means of adjusting the speed and generation output of the turbine. Blade pitch also enables the system to obtain a rotational speed best suited for conversion to the electricity frequency required for export to the electrical distribution grid. The turbine may, for example, have its blades pitched to only catch some of the wind and so operate at a lower rotational speed, reducing wear and tear on the wind turbine when the wholesale electricity price is low, for example, on a sunny afternoon when there is less demand.

The use and complexity of preventative maintenance systems is increasing, for example monitoring the vibration of rotating shafts and the wear of shaft couplings.

Contrinex analogue inductive sensors combine high precision with sensing ranges of up to 40mm, combined with precision measurement accurate to a few microns. Analogue inductive sensors located in the rotor measure the distance to an eccentric lobe attached to the end of each blade to monitor the angle or pitch of the turbine blades. They provide a robust and precise system to replace more costly and fragile mechanical encoder solutions. The increasing placement of wind turbines in challenging environments with prolonged exposure to outdoor, often salt-laden air further enhances the advantages over encoder systems.

The fine resolution of the sensor's measurement also enables their use in monitoring rotating shafts to look for vibration or track trends in movement as bearings wear, replacing the use of maintenance based on time or rotational count. Another application measures the distance to a shaft coupling, providing a simple analogue voltage or current to the PLC. The precision of Contrinex's analogue inductive sensor enables the movement as the seal wears over months and years to be measured and used as part of a preventative maintenance system to schedule the best time for coupling replacement.