Research And Development Of Eddy Current Metallic Debris Sensor

Oil monitoring is an important technical means in equipment condition monitoring and fault diagnosis which has been widely used in the industrial field.As an important content of oil monitoring,metallic debris monitoring can effectively obtain the debris information in real time is of great significance to wear evaluation and early fault warning.Due to the simple structure,real-time monitoring,rapid response,the electromagnetic oil debris monitoring sensors have shown a broad application prospects in the field of metallic debris monitoring.However,the commonly used electromagnetic oil debris monitoring sensors are susceptible to debris continuity and cannot identify debris material.Based on this,a metallic debris monitoring sensor based on the eddy current technology has been developed through theoretical analysis and experimental research in this paper.The main research contents include:(1)The principle and the equivalent circuit of the eddy current sensor is studied.By doing this,the parameters that affect the output of the eddy current sensor are obtained.Then the electromagnetic simulation is conducted by the magnetic simulation software.The influences of the excitation frequency,the inner diameter of the coil,the material and the size of the debris are analyzed.The results provide the theoretical guidance for the design of the sensor induction coil and signal processed circuit.(2)Based on the result of the electromagnetic simulation,the induction coil and signal processed circuit of metallic debris sensor are designed.Then,the function of signal processed circuit is simulated by QUCS(Quite Universal Circuit Simulator),which verifies that the feasibility of the signal processed circuit.(3)According to the design of the induction coil and the signal processed circuit,a sensor circuit board was manufactured and a sensor test platform was set up.Then iron and copper debris with different sizes were selected and tested.The characteristic parameters of debris were extracted and the ability to detect metallic debris of the sensor was verified.(4)The characterization formulas of iron debris and copper debris are obtained by dealing with test data,the size and the material identification are realized.Then,the “Metallic Debris Online Monitoring System” are developed and tested,the purpose of online monitoring of metallic debris were achieved.The results in this paper can provide a new idea for the metallic debris monitoring and provide a new perspective for the industrial application of eddy current theory.They are of great significance in preventing equipment wear failure,reducing major accidents and economic losses.