Functional principle and sensor construction
The present technique for a contact-less determination of various mechanical parameters has been developed and patented at the HZDR and HZDR Innovation GmbH. The sensor does not require any treatment or any alteration of the measurement object. The sensor head consists of several inductances, which are arranged in a close circumference of some millimeters to the measurement object. One of these coils is fed by an electrical current at a constant frequency. The equidistant located receiver coils act as a passive part of the sensor, which behaves like an intersected transformer. The detection of torque- or speed-dependent phase shift between the input and the received signals is accomplished by an innovative sensor electronics. The underlying analysis software reduces drift and interference effects for instance caused by thermally driven effects or material-specific hysteresis effects.