Apparatus for measuring and changing vibration frequency of metal B

摘要: A method of measuring and, where necessary, modifying the natural vibration frequency a metal bar, more especially ferromagnetic comprising freely suspending bar in constant magnetic field, subjecting to action from outside make it vibrate and detecting resulting frequency. There is also provided apparatus for carrying out method, which comprises vertical insulating cylinder, at center kept suspended by pneumatic device, means intended vibrate, solenoid establishes field terminals detected, selective amplifier connected solenoid.