Development of Metallic Wear Debris Sensor Based on Eddy Current Technique

On-line detection of metallic wear debris is an effective approach for condition monitoring of mechanical systems. Existing on-line oil conditioning sensors are mainly based on ferrography and inductive techniques. However, ferrography technique needs a clean background and inductive technique requires a high cleanliness of lubricant. To solve these issues, in this paper a metallic wear debris sensor based on eddy current principle is developed. Both numerical simulations and prototype experiments are conducted to evaluate the capacity and feasibility of the new sensor for detecting wear debris. The analysis results demonstrate that: 1) A pulse is generated when the wear debris pass through the sensor, the amplitude and width of the pulse can be used to identify the material and size of the debris; 2) The developed sensor is able to detect copper debris with a diameter greater than 150 μm and iron debris greater than 60 μm. This work provides a new idea for detecting wear debris and a new method for obtaining the characteristics of wear debris.