Wind turbine bearings, yaw and pitch bearings are supplied with standard lithium-based grease unless there are special user requirements. If grease is added during installation, the internal space of the bearing generally needs to be filled. After the bearing is installed and put into service, check and refill the grease once after 100 hours of continuous operation. The lubrication cycle is based on usage and environment. We recommend lubrication every 150 hours under normal circumstances. If the usage requirements are strict or in a dusty or humid environment, the lubrication cycle should be shortened to 50 hours. Grease should be added before or after prolonged cessation of use. If it is stopped for a longer period, it should be lubricated every 6 months.
There must be lubrication holes in the radial direction of the bearing, et a grease gun can be used to add grease. Before installing the oiler or connecting pipe, remove the plastic plug or threaded plug from the oil hole. When adding grease to the raceway, it should be evenly lubricated and rotated at a slow speed. It is normal to see a small amount of new grease escaping onto the oil seal lip.
1. Time domain fault diagnosis method
Time domain statistical characteristics are the most commonly used monitoring parameters in vibration monitoring of wind turbine main bearings, which can effectively detect bearing faults wind turbines. serious accidents. When the main bearing of a wind turbine fails, the vibration amplitude of the bearing increases significantly and a corresponding impact signal is generated. The trend of changeVibration amplitude is represented by the average value. This parameter results in irregular vibrations and is not sensitive to early bearing failure. The kurtosis xq, peak value xP-p and impulse index I are very sensitive to the small impact present in the vibration signal, which improves fault identification. The peak index xP-p is generally used to detect impact vibrations caused by bearing peeling, cracks, etc., while the flattening index xq is used for the earliest fault diagnosis of the bearing. The K waveform indicator is often used to detect mechanical failures caused by discrete defects such as pitting, scoring, peeling and scratching in various bearing components. This type of failure does not have excessive total waveform energy, but exhibits high peak values. Plus the value of the index of fThe higher the waveform, the more serious the bearing failure.
2. Frequency domain fault diagnosis method
In the process of fault diagnosis of wind turbine main bearings, the characteristics of bearing faults are generally modulation phenomena, and the waveform in the Time domain of the vibration signal is relatively complex and cannot intuitively express the characteristics of the fault signal. The vibration frequency signal is objective and can better reflect the basic characteristics of the vibration signal. The time domain vibration signal is converted into a frequency domain vibration signal via Fourier transform, and the spectrum can intuitively reflect the energy size, frequency composition and phase of the vibration signal. However, the frequency domain fault diagnosis method is only suitable for ifstationary signals. Since the Fourier transform method is a global transform, the sampling rate of the system is directly related to the resolution. It is impossible to obtain the specific frequency corresponding to a specific frequency. time and the corresponding appearance time of a specific frequency. Therefore, the frequency domain fault diagnosis method is not representative for the analysis of non-stationary vibration signals.
3. Time-frequency fault diagnosis method
The time-domain fault diagnosis method and the frequency-domain fault diagnosis method both have certain limitations, which cannot well reflect the completeness and locality of the vibration signal. Therefore, a new diagnosis method is proposed, which is the time domain fault diagnosis method. Frequency fault diagnosis method.The time-frequency fault diagnosis method organically combines the time domain and frequency domain into a video phase plane to obtain spectrum diagrams of vibration signals at different times. Currently, widely used time-frequency fault diagnosis methods include Hilbert-Huang transform (HHT) and envelope mediation method. The envelope demodulation method uses envelope detection and spectral analysis of the envelope signal, then diagnoses and identifies defects based on the demodulated spectrum peaks. The envelope demodulation method is particularly suitable for high-frequency impact vibrations. Until now, the envelope demodulation method remains the only effective and important analysis method for high-frequency impact vibrations. Envelope demodulation method is mainly used for high-precision fault diagnosisof the main bearings of wind turbines. It can not only diagnose the fault location, but also determine the fault type.