| Cooling tower fan system is mainly applied in electric power, metallurgy, petrochemical, and other industrial production. It is an important part of air cooling equipment, which bears the important function of cooling and recycling of industrial water to ensure that the industrial continuous production runs smoothly. The structure includes motor, drive shaft, gear reducer, leaf, the wheel hub etc. In high temperature and large humidity environment operation, it’s easy to produce the corrosion and the rust scale which makes work component failure and produces mechanical failure and causes large area of equipment damage when the situation is serious and even appears economic or personal casualty.The paper analyzed the cooling tower fan system in the following aspects:First of all, the failure investigation and survey of cooling tower fan system was carried and the usual failure part and the forming of the failure of cooling tower fan was found. The paper elaborated the failure mechanism of drive shaft, gear and blade of cooling tower fan and the preventive measures was found out. The key components of cooling tower fan were protected, so service life of cooling tower fan was prolonged and the work efficiency was increased.Secondly, the paper took the fan vibration signal as the research object and found some typical characteristic failure signals through the analysis of time domain and frequency domain and took them as monitoring signals,and feedback control signals of cooling tower fan operating condition.Thirdly, the paper stated a variety of signal frequency processing methods and analyzed short time Fourier transform, wavelet transform, wavelet packet analysis and EMD analysis theory and compared the good and the bad they deal with cooling tower fan signals and also summarized improving t heretical ana lysing method. So it is confirmed that the wavelet analysis EMD analysis method was applied as the processing method of cooling tower fan vibration signals.Then, the paper simply expounded automatic control theory and analyzed the advantage and the disadvantage of open loop and closed loop system. Combined with the operation analysis to cooling tower fan system, the closed loop control system was applied to monitor voltage current, oil temperature and liquid level. The vibration characteristic signal of driving shaft, gear box and blade was taken as feedback to indicate cooling tower fan operation state and monitor and control the state of cooling tower fan.Finally, the paper analyzed the effects caused by failure diagnosis monitoring and control to cooling tower fan and the advantage and the disadvantage of this system through the simulation signal. Acquisition The specific cooling tower fan vibration signal was acquired to guide the maintenance worker to the system inspection and maintenance schedule through contrast processing and finding fault form and position. |
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