Research on Three-Coil Magnetically Coupled Resonant Oil Abrasive Particle Detection Sensor

Oil is vital to the stable operation of mechanical equipment, providing energy transfer, lubrication, and cooling. Analyzing abrasive particles in oil is essential for effective maintenance of equipment. In order to improve the signal transmission distance and quality of the oil detection sensor, this article presents a novel three-coil magnetically coupled resonant sensor structure for detecting wear particles in the oil. This innovative design utilizes the interaction between the magnetic field generated by the excitation coil and the magnetization and eddy current effects produced by ferromagnetic and nonferromagnetic metallic wear particles in the detection area to generate variable inductive signals. By analyzing the characteristics of these signals, the sensor can clearly distinguish the size and type of different metal particles. This structure achieves noncontact detection of particles in oil through electromagnetic coupling between the coils, while the addition of a relay coil greatly improves the signal transmission distance and quality of the sensor. Simulation results confirm that this sensor design can greatly improve the signal transmission distance and detection quality with an optimal transmission spacing of 0.5 mm. The experimental results showed that the sensor was able to detect iron particles at $73~\mu $ m and copper particles at $220~\mu $ m. The signal amplitude for the detection of iron particles was dramatically increased by a factor of about 133, and that of copper particles by a factor of about 29. The novel sensor structure for oil wear particle detection proposed in this study provides a promising new approach for noncontact oil detection sensors.