The bearings of the drive end and non drive end of the condensate water pump for a certain dry quenching plant are both 6310, with a speed of 2981 RPM. After calculation, it is:
Outer ring characteristic frequency BPOF=151.4 (Hz)
Inner circle characteristic frequency BPIF=245.8 (Hz)
Rolling element characteristic frequency BSF=196.6 (Hz)
Cage characteristic frequency FTF=18.87 (Hz)
Through vibration monitoring, the entire process of bearing installation and failure can be traced.
In the initial stage of bearing failure, the frequency range is approximately between 20 KHz and 60 KHz - or higher. There are various electronic devices available to detect these frequencies, including peak energy, HFD, impulse pulses, SEE, and other ultrasonic measurement devices. At this stage, there will be no display on the regular spectrum. The following figure shows no frequency of bearing failures after installation.
In the second stage, the natural frequency generated by slight defects in the bearing and the resonance frequency may be used as the carrier frequency to modulate the fault frequency of the bearing.
In the third stage, as bearing wear further intensifies, the peak value will linearly increase over time and the frequency of faults will appear on the spectrum. Some bearings have bearing defects at the frequency of installation, but it may not necessarily be damage, mainly depending on the presence of harmonic frequencies. After running for a period of time, the speed spectrum shows the frequency of outer circle faults and the envelope spectrum shows the frequency of inner circle faults.
In the fourth stage, the fault frequency will generate harmonics, indicating that a certain degree of impact has occurred. The harmonics of the fault frequency are sometimes detected earlier than the fundamental frequency peak, and impulse pulses will also appear in the time-domain waveform.
In the fifth stage, there will be more harmonic faults in the bearings. Due to the nature of the faults themselves, there will also be sharp peaks on the time-domain waveform of the sideband, which will be clearer and more obvious for high-frequency bearing detection, such as a continuous increase in peak energy and impulse pulse trends.
In the sixth stage, the amplitude of the rotational speed frequency increases and a 1X harmonic appears, which is the result of increased clearance caused by wear.
In the seventh stage, the fault frequency and its sidebands become peaks and hills, often referred to as "haystacks.". The noise emitted by the bearings can still be heard, and the temperature of the bearings increases, but high-frequency bearing measurements may gradually decrease.
In the eighth stage, the "haystack" in the spectrum will continue to expand, and the harmonics will increase with the increase of looseness. The trend of high-frequency bearing measurement values will continue to decrease, and the overall noise level will increase. The abnormal sound emitted by the bearing can be clearly heard, and the abnormal temperature rise of the bearing indicates that the bearing is about to be scrapped.
2024 April 3rd Week VAFEM Product Recommendation:
Water pump bearings are double row bearings and, in contrast to conventional double row bearings, do not have an inner ring but raceways machined directly into the surface of the shaft.
As a precious high quality water pump bearings manufacturer and supplier in China, VAFEM can guarantee the quality and precision of the products through complete testing technology and advanced equipment. Please come to buy water pump bearings at the best price and quality from VAFEM. Please contact us for any questions!
https://www.vafem.com/products/Water-Pump-bearings/847.html
2024-04-19