Non-destructive electrically conducting material testing - using magnetic fields of different fields and variable control signal detector (SW 3.7.78)

摘要

The method and device enable non-destructive testing of materials of electrically conducting material, e.g. mouldings, metal tables, blanks etc., for faults, dimensional changes etc. including those due to external influences such as speed and force. They involve applying magnetic fields of two or more different frequencies and using one or more signal pick-ups with a coil or wire loop whose output is nulled for no object change. The device uses a position reference eliminating vibration errors. This does not have a minimum distance limit. A controlled detector is used. The detector control signal is variable.