Electromagnetic Detection Sensor Simulation For Lubricating Oil Metal Grindings

Lubricating oil is mostly used to lubricate and cool power machinery equipment, it will carry away the pollutants generated by the system during cycle process. These pollutants can easily cause wear-out failure of machinery. By monitoring solid contaminants in the oil, we will get the status information about machine system.The traditional off-line detection method has high sensitivity and needs off-line achievement but it’s less efficient and expensive. So the study of online monitoring method with more effective has great theoretical significance and practical value.This paper builds a mathematical model of electromagnetic spiral sensor based on Biot-Safar Law and uses Ansoft Maxwell software to simulate the inductance characteristics of the model. The minimum radius of the oil abrasive grains detected by the model is 50 um.When different grains go through the sensor, we can get inductance value under different circumstances, Irregular shape grains which produced by mechanical movement can easily form aggregation.The paper studies the inductance characteristics of dual abrasive particles and the relationship between per unit density and the output signal, then it explores inductance characteristics of multi-grains in a variety of angles which include inductance value, magnetic flux, coupling coefficient and so on. Considering the difference of system arrangements, the sensor structure will be demanded.This paper presents three coils parallel electromagnetic sensors and embedded electromagnetic sensors, and does a comparison of magnetic characteristics between the two style sensors. Due to the irregular shape of the abrasive grains,the paper takes ball abrasive grains and cylindrical abrasive grains as examples to make a series of simulation to verify the shape of abrasive grains influence on the inductance characteristics.Finally, the grain detection system based on simulation models of inductive sensor has been built. This system uses traditional parallel three-coil structure sensor as a part of sensing elements, and realizes the detection for a single grain of different size. By measuring conditioning circuit which includes amplification and rectification as well as filtering,different voltage signals have been obtained which is used to verify the simulation.