Extraction of weak signal based on wire rope detection in timing belt of wind turbines

As promising non-destructive testing (NDT) method, magnetic flux leakage (MFL) testing has been widely applied for steel structure detection. However, magnetic flux leakage (MFL) signal collected by the sensors is weak, especially for the small diameter wire rope. The methods of using the traditional circular coil sensors, or increasing the number of magnets is ineffective in some situations. This study proposes a new method of highly sensitive long-strip-shape coil sensors with an analogue signal processing circuit used to detect wire rope in the timing belt of wind turbines. It is investigated by theory analysis, circuit simulation, and experiment conduction. The circuit is used to amplify the weak signal and filter high-frequency noise to obtain a high signal-to-noise ratio (SNR). Experiments show that the resolution of the method can reach 3 broken wires of 0.1 mm wire diameter, and the method can not only obtain a high SNR signal but also have good repeatability. Meanwhile, this method will have great significance in practical applications and provide some solutions for other similar NDT projects.