An Inductive Debris Sensor Based on a High-Gradient Magnetic Field

The health condition of mechanical systems can be characterized by wear debris in lube oil. Therefore, wear debris detection is necessary for the fault prediction and diagnosis of mechanical systems. This paper presents an inductive debris sensor based on a high-gradient magnetic field. An induction coil is placed in a high-gradient magnetic field, and an induced voltage is generated when wear debris in the oil pipe flows through a magnetic field. A mathematical model of the sensor is established, and the output signal of the sensor is similar to that of a three-coil inductive debris sensor. The experimental results show that the sensor is capable of detecting 25-μm ferromagnetic particles. The sensor driven by a constant current has a simple structure and is feasible for on-line wear monitoring.