Piezoelectric Patch Transducers: Can alternative sensors enhance bearing failure prediction?

Abstract

This paper examines the applicability of piezoelectric patch transducers as condition monitoring sensors for the drive train of wind turbines. Three laboratory experiments are conducted to determine the sensor's temperature stability, sensitivity toward electromagnetic interference and general ability to detect bearing damages. The sensors show little deviation under thermal influence in a tested temperature range between -40 ?C and +80 ?C. Although they react to electromagnetic interference, the disturbance signal is predominated by the damage signal. Proper shielding is yet recommended to fully eliminate electromagnetic interference. An example of shielding is given through the use of mu-metal. In direct comparison of bearing fault detection capability to a state-of-the-art accelerometer, the patch transducer performs slightly worse in matters of signal-to-noise-ratio. However, when excited by small damage impulses, it yields good signal depth and output. Altogether, the sensor shows fundamental applicability as a condition monitoring sensor in all experiments, though further optimization seems feasible and worthwhile.