Magnetic characteristic of unferromagnetic wear debris in inductive wear debris sensor

When unferromagnetic wear debris is in the coil of inductive wear debris sensor,the magnetic field distribution of the coil is changed through eddy effect,and then the equivalent inductance of the coil is changed.The finite element model of coupling relationship between the coil of sensor and the unferromagnetic spherical wear debris is built.The computed results of the model show that the eddy field of the wear debris cut down the magneic induction density inside the wear debris,and the magnetic induction density outside the wear debris is changed.The change rate of sensor coil inductance increases with driven frequency increasing,and approaches a limit.And the rate of change of sensor coil inductance decreases quickly with wear debris' radius decreasing.The results of the test prove that the model is correct.