Wear particle is an important factor which causes mechanical failure. Solenoid sensor is commonly used to detect wear particle. Focus on situation of multilayer coil winding based on solenoid sensor and put forward a sensor with three-coil inner and outer layer structure. Depending on circuit theory

derive working equivalent circuit of sensor and magnetic induction intensity formula and inductance formula of multilayer coil. Compare magnetic field of both inner and outer layer and parallel type wear particle sensor and analyze impacts of coil winding layer number on sensor output characteristic

which is based on Maxwell. Simulation results show the correctness of formulas and provide basis for design and optimization of multilayer coil wear particle sensor.