Inductive debris sensor using one energizing coil with multiple sensing coils for sensitivity improvement and high throughput

Inductive oil debris monitoring has been widely used in the prognosis of machinery faults. This work proposes a new structure of inductive debris sensor that provides sensitive debris-sensing capability. This structure, which includes multiple sensing coils inside an energizing coil, considerably differs from traditional structures. Theoretical analysis shows that the proposed structure can significantly improve sensitivity. The sensor with two semicircular sensing coils is preliminarily designed and tested. The performance of the sensor is evaluated using a simple and efficient test platform. Experimental results show that the designed sensor can identify 120 μm (D) ferrous particles and 210 μm (D) non-ferrous particles in a pipe with an inner diameter of 34 mm.