Abstract: A torque sensor is used for non-contacting measurement of torques in accordance with the eddy current principle. This sensor is arranged closely in front of the surface of the test object (shaft). The torque is determined on the basis of permeability changes in the surface of the test object material. There is a state of dependence between the measuring voltage and the distance of the torque sensor from the test object. As the distance increases, the measuring voltage decreases. The measuring voltage acquires a substantial distance independence by virtue of the exciting winding of the torque sensor forming with a capacitor a resonant oscillatory circuit tuned to the exciting frequency.

Abstract: A method and apparatus for measuring static or dynamic torques on a test piece, in a contact free manner is possible where the test piece is made of magnetically permeable material which permeability changes due to the occurrence of torques on the test piece. These changes are sensed by the apparatus of the invention, according to the method of the invention, utilizing a four pole test probe forming a magnetic bridge.