Demagnetization Fault Diagnosis of Magnetic Coupler Based on STFT-S

Magnetic coupler (MC) has been widely used in petroleum, chemistry and other industrial fields. However, demagnetization faults are easy to occur in permanent magnets when transporting high-temperature media. Demagnetization faults are difficult to detect due to the double-rotor structure of MC. To solve this problem, a demagnetization fault detection device for MC is established, and a short time Fourier transform method based on speed window function (STFT-S) is proposed. The demagnetization degree and fault pole location of MC under nonstationary conditions of velocity is determined by analysing the time-frequency characteristics of the STFT-S transform. Finally, the finite element simulation results verify the effectiveness of the proposed method.