Improving SNR of MFL Signal in Flaw Detection of Coal Mine Wire Ropes

Magnetic flux leakage detection (MFL) is widely used as an effective method in detection of broken wires of ropes. In order to improve the accuracy of flaw detection using MFL signal, the effect of the distance between a sensor and the surface of a wire rope (i.e. lift-off) is investigated. The main principles for the choice of lift-off are analyzed, and a method is proposed from the point of view of the magnetic circuit design to restrain the impact of fluctuations of sensor lift-off and improve the signal-tonoise ratio (SNR) of MFL signal. The method is validated through computer simulation and laboratory experiment. The results show that the SNR of MFL signal in flaws detection of wire ropes can be increased by over 25%.