A Fault Diagnosis Method For Motor Bearings Based On Spectrum Estimation With Multiple Sinusoidal Tapers

The induction motor has been applied widely on vessel.It has low cost,high reliability and simple structure.The induction motor sustains propelling system and power system so the security of marine navigation will be threatened if one motor has fault.Diagnosis system of fault for marine induction motor is very important to the security of marine navigation.As bearing fault has the highest probability in all faults of motor,this paper researches into the bearing fault diagnosis system for marine induction motor.The main content of this paper is comparing and confirming the diagnostic method of bearing fault,researching for a better way to pick up the character of bearing fault and designing and making up of the on-line diagnosis system of bearing fault for marine induction motor.Considering the especial condition on vessel and the character of bearing fault for induction motor,this paper chooses Motor Current Signature Analysis(MCSA) to diagnose bearing fault for marine induction motor after comparing several method of fault diagnosis for marine induction motor.MCSA establishes function between the eigenfrequency of motor current and the character of bearing fault.As long as picking up the character of bearing fault in motor current,the existence and the type of bearing fault can be diagnosed.The induction motor has a very noisy backrgound condition on vessel.The rate of Signal-to-Noise for bearing fault character is low.and it is hard to pick up the character of bearing fault because it is very weak and polluted by noise.Comparing FFT with power spectrum estimation and the Slepian multiple taper spectral estimation,this paper chooses sinusoidal multiple taper spectral estimation to pick up the character of bearing fault for induction motor.It does some simulation analysis to choose the sampling frequency,number of window function and sampling number for the better effect.About the hardware,This paper chooses hall element to measure motor current in the diagnosis system and Digital Signal Processor TMS320F2812 to processing signal with the method of sinusoidal multiple taper spectral estimation.The MAX3160 multi-consultative transceiver is used to constitute the asynchronous serial communication and on-line fault diagnosis system.About the software,this paper makes A/D conversion for the signal and designs the program of sinusoidal multiple taper spectral estimation.It also designs the program of the asynchronous serial communication and the supervisory computer to complete the on-line fault diagnosis system.