Sensors aid tidal turbine development

Non-contact torque sensors from Sensor Technology are used in the development of commercial-scale in-stream tidal turbines produced by OpenHydro.

The company uses the sensors, which are based on surface acoustic wave (SAW) technology, to accurately measure rotational speed and frictional forces in a simulator for the turbine bearings.

The simulator allows engineers to determine how frictional forces in bearings vary with different loads and rotational speeds. Central to this is the measurement of torque in a shaft from the motor that drives the bearing under test. TorqSense RWT3 series sensors provided a solution.

The units depend on SAW transducers that comprise two thin metal electrodes, in the form of interlocking 'fingers', on a piezoelectric substrate such as quartz.

Since the transducers operate at radio frequencies, it is easy to couple signals to them wirelessly. Hence TorqSense sensors can be used on rotating shafts, and can provide data continuously without the need for brushes and slip rings.

OpenHydro uses the RWT320 sensor in conjunction with Sensor Technology's TorqView software.