This paper puts forward a kind of gearbox fault diagnosis methods which based on empirical mode decomposition (EMD), Hilbert transform, Fast Fourier Transform (FFT) and spectrum refined techniques. This method is applicable to the analysis of the nonlinear unsteady signal. First of all used wavelet denoising to the acquisition of gearbox vibrate signal, again carries on the empirical mode decomposition (EMD), than get a certain number of intrinsic mode function (imf); Choose the specific imf, based on kurtosis value, after the Hilbert transform and Fast Fourier Transform is done, the corresponding power spectrum can be obtained; To refine the power spectrum and extract the gearbox fault characteristic frequency; Then in pattern recognition and diagnosis of the gearbox fault, and compared with the normal signal characteristics. The analysis results show that the proposed method can effectively detect the gearbox fault characteristics.
When generator operates normally, armature reaction magnetic fie]d synchronous]y rotates with rotor, and rotor winding won't induce additional harmonic current, When stator winding hnd r6tor wlnding inter-turn short circuit fault has happened, armature reaction magnetic fie]d non-synchronous]y rQtates with rotor. so additional harmonic current is induced in rotor winding. Through analyzing electromagnetism charactcristic on stator and rotor winding fault respectively, it is known that the additional excitation current harmonic on stator winding fau]t mainly is twice electrica] frequency, and that on rotor winding fault is the function ofair-gap excitation magnetic field harmonic frequency, po]es' pairs ofgenerator and rotor mechanica] revolution.Finally, the excitation current of MJF-30-6 synchronous non-salicnt pole generator is acquired on stator and rotor winding jnter-turn short circuit fault respectively, the results of verification show that the theory analysis is right,
Because some composite insulators run certain number of years and tends to exist insulation breakdown performance degradation issues, and some even mass incidents have occurred, affecting the normal operation of the grid. First introduced X-ray inspection systems, then introduction common failure and the reason of composite insulators. And through the artificial gap between the mandrel and the jacket seams, V-shaped mandrel and an artificial scratches and other defects between the insulator strings, concluded the feasibility of X-ray diagnosis of common faults of composite insulators.
Through the visual inspection, the appearance of size measurement, crimping size measurement, the steel core crimping length measurement and steel core tensile strength test of tension crimp barrel on 220kV transmission line. Made a detail analysis on test results combined with wire crimping theory. Pointed out the wire crimping defects caused by crimping irregularities. Analyzed the main causes of rupture accident, and made recommendations for improvement. Provides a reference to wire crimp and wire accident analysis.
The advantages and disadvantages of traditional gearbox fault diagnosis method based on autocorrelation, spectrum-zoom, Hilbert demodulation and cepstrum analysis are respectively analyzed. Then a gearbox fault diagnosis method is presented, which integrates autocorrelation, spectrum-zoom, Hilbert demodulation and cepstrum analysis. Finally, vibration data of the pitting gear is measured by using QPZZ-II rotating-machinery fault simulating system. The result shows that the improved method proposed in this paper is effective for the fault diagnosis of the pitting gear.This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications.. The best is to read these instructions and follow the outline of this text. Please make the page settings of your word processor to A4 format (21 x 29,7 cm or 8 x 11 inches); with the margins: bottom 1.5 cm (0.59 in) and top 2.5 cm (0.98 in), right/left margins must be 2 cm (0.78 in). We shall be able to publish your paper in electronic form on our web page http://www.scientific.net, if the paper format and the margins are correct. Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.
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