Torque Sensor Using Amorphous Star-Shaped Core Magnetic Field Sensor

A method for measuring the torque exerted on an induction motor shaft by detecting differences in the shaft angles of twist is reported. A pair of precise twist angle sensors, consisting of multiple pole magnet rings surrounded by radial arrays of amorphous magnetic core field-sensitive elements, with their outputs 90° out of phase, are used to detect the angle of twisting of the shaft, from which the torque is determined. The sensor output was found to be highly linear with respect to the actual torque.