A Three-Coil Wear Particle Sensor Based on Radial Magnetic Field

Presently, researches on wear particles detection of oil in mechanical equipment primarily focus on improving accuracy and increasing throughput but rarely involves errors detection caused by different particle positions. This paper presents a three-coil wear particle sensor based on radial magnetic field. The unique coil layout structure ensures a uniform internal magnetic field within the detection coil. Consequently, the generated voltage signal error is minimal when particles pass through sensing area from different radial positions. By utilizing theoretical formulas, a mathematical model is developed for the wear particle sensor. The magnetic flux density distribution in sensor's channel is simulated. Meanwhile, the induced voltage signals characteristics of ferromagnetic and non-ferromagnetic particles are obtained. Experimentations demonstrate that the sensor with radial inductive three-coil could measure 50μm iron particles and 275μm copper particles in the 2mm channel. It is proven that the sensor's detection error is below 10% by calculating the amplitude of induced voltage signals produced by pellets going through center, upper edge, and right edge of the sensor's sensing area via experiments. This study enhances the application of inductive three-coil sensors in oil monitoring as well as provides new research insights for reducing sensor detection error and improving sensor detection accuracy.