Torque sensor is a transducer that converts a torsional mechanial input into an electrical output signal.Rotary torque sensor is designed to measure rotating torque like motor torque , rotating shaft torque,mixture torque,etc..Rotary torque transducer can also be used to measure static torque(which is also known as reaction torque).
Rotational sensors (or dynamic torque sensor) are utilized in applications where the torque measurement must be taken at a spinning shaft, engine or a stationary motor. In this case, the transducer must rotate in-line attached to the shaft. A rotary torque transducer is fitted with a slip ring or wireless electronics to transmit the torque signal while rotating (non-contact sensor).
Rotary Torque Transducers are frequently used as testing/auditing tools for motors, torque measuring tool, turbines, and generators to measure rotational torque. A shaft-to-shaft Rotating Torque Sensor can be also utilized for feedback control, monitoring torque, and analyzing the efficiency of test stands and for torque measurement of rotating shaft using strain gauge.