How do you calculate bearing fault frequencies?
Formulas for the calculation of the bearing failing frequencies
- BPFO=0.4×NB×RPM.
- BPFI=0.6×NB×RPM.
- FTF=0.4×RPM.
What is bearing fault frequencies?
The bearing natural frequencies depend on the dimensions of the bearings and how these are mounted. Typically, the natural frequencies can be found in the 2-6 kHz range. At the end of stage two, sidebands appear above and below natural frequencies and high-frequency detection method continues to increase.
How do you check for bearing failure?
Bearing failure is indicated by high vibration. The fundamental and harmonics begin to actually decrease, random ultrasonic noise greatly increases, temperatures increase quickly. Remaining life one hour to one percent.
What is the fundamental train frequency?
The fundamental train frequency is the frequency at which the roller cage entering and exits the load zone. The ball pass frequency is the rate at which a defect in the inner or outer race comes into contact with a roller.
What is gear mesh frequency?
The tooth-mesh frequency, also called gear-mesh frequency, is the rate at which gear and pinion teeth periodically engage: f Mesh = f Pinion × N p = f Gear × N g .
What is fault frequency?
Fault frequencies, sometimes called fault-forcing frequencies are the frequencies at which a faulty part will generate forces on a machine. An example is the Ball Spin Frequency (BSF) in a bearing. The fault frequencies are used as tell tale tones in a machine spectrum for diagnosing internal faults.
What is a bearing fault?
So, what is a bearing failure? A bearing failure occurs when the bearing fails to meet their expected life or performance levels, often causing a machine shaft to fail, and the machine it is apart of can break down. The consequences of bearing failure are far-reaching for your facility.
What causes ball in bearing to fail?
The most prevalent causes of misalignment are: bent shafts, burrs or dirt on shaft or housing shoulders, shaft threads that are not square with shaft seats and locking nuts with faces that are not square to the thread axis. Serious misalignments introduce excessive vibration and loads.
What are the four types of fault frequencies in bearings?
Faults in any of the four bearing components will generate specific frequencies dependent upon the bearing geometry and rotating speed. These four fault frequencies are commonly termed: BPFO – Ball Pass Frequency, Outer Race BPFI – Ball Pass Frequency, Inner Race BSF – Ball Spin Frequency FTF – Fundamental Train Frequency.
What are the frequency bands for the analysis of bearing condition?
Frequency bands for the analysis of bearing condition Spectral parameter Bandwidth Imbalance, missalignment, looseness, rub 1.5 to 2.5x RPM Missalignment and looseness. 1.5x to 2.5x RPM Looseness, missalignment and BSF. 2.5 to 4.5x RPM First harmonics of the bearing fault fre 4.5 to 20.5x RPM
What are the characteristics of a high frequency bearing?
Higher bearing fault frequencies harmonics and presence of frequencies related to electrical issues. High frequency spectral band, in units of acceleration (G’s). Alarm parameter in case of early bearing deterioration stage, presence of cavitation or lack of lubrication.
How do I generate fault frequencies for a Cooper bearing?
Simply select the bearing from the database, then enter the machine running speed, to generate the desired fault frequencies. – All Cooper Bearing Numbers included in our database are in Metric designation. – Using a different manufacturers’ data, for the same bearing number, may yield an errouneous value.