Research on the Influence of Excitation Frequency on the Sensitivity in Metal Debris Detection with Inductor Sensor

Abstract

The nonferromagnetic debris is easier to be detected as the excitation frequency increases; however, the sensitivity of ferromagnetic metal debris decreases as the excitation frequency increases. This paper is aimed at finding a range of excitation frequency that fit both ferromagnetic metal debris detection and nonferromagnetic metal debris detection. The equivalent circuit of the metal debris detection system with microinductor sensor is analyzed in this paper. The formulae of relationship between the sensitivity and excitation frequency are achieved according to the equivalent circuit. The simulation model of metal debris detection with the microsensor coil is built with the Ansoft software. The equivalent inductance and the electromagnetic induction field of the microinductor sensor are simulated as the excitation frequency changed. The experimental test is carried out with the prototype of microinductor sensor. The simulation results and the test results are compared. The studies indicate that the relationship between the excitation frequency and the changing rate of sensor inductance can be described by the fitting formulae. A higher sensitivity can be obtained if a suitable excitation frequency is selected. These researches have reference value for the design of inductor sensor and the parameters setting in the experimental test.