Joint domain: Because vibration signals vary with time, calculating more than one spectrum at once can be useful.Most in-depth analysis of machinery vibration is done in the frequency domain or using spectrum analysis. The spectrum is in the frequency domain like the vibration is in the time domain. Frequency domain: When the waveform discussed earlier is subjected to spectrum analysis, the end result is a picture of frequency vs.While most machine vibration issues are detected using spectrum analysis, some types are more easily seen in waveform. The time domain is amplitude plotted against time. Time domain: When a vibration signal is picked up from a transducer (device that converts a physical quantity into an electrical signal) and displayed on the screen of an oscilloscope, it's called a waveform.Vibration analysis is generally broken down into four principles, and each principle gives you specific information on the working conditions and features of the vibrating parts. This allows for a more accurate and more localized analysis, and opens up vibration analysis to more methodology. While accelerometers are still the most common tool used to collect vibration data, modern technology and improved sensor technology have allowed for non-contact, high-speed laser sensors that can detect issues accelerometers can't. If three bearing rollers hit the spall per revolution, you should see a vibration signal of three times the fan's running speed. Another example would be a damaged bearing track causing a bearing roller to generate vibration each time it contacts the spall (similar to a pothole on a highway). This unbalanced force will occur one time per revolution of the fan. As expected, the fan vibrates due to an unbalanced fan wheel. Empty space or bubbles (cavitation) in pumpsĭistributor and alignment and maintenance training provider VibrAlign uses the example of taking an industrial fan, removing a fan blade and starting it up.Vibration analysis can detect problems such as: All of this data is analyzed by computer program algorithms, which in turn is analyzed by engineers or trained vibration analysts to determine the health of the machine and identify possible impending problems like looseness, unbalance, misalignment, lubrication issues and more. frequency (known as fast Fourier transform), or both. time (known as time waveform), amplitude vs. An accelerometer attached to the machine generates a voltage signal that corresponds to the amount of vibration and the frequency of vibration the machine is producing, usually how many times per second or minute the vibration occurs.Īll data collected from the accelerometer goes directly into a data collector (software), which records the signal as either amplitude vs. Anytime a piece of machinery is running, it is making vibrations. While the inner-workings and formulas used to calculate various forms of vibration can get complicated, it all starts with using an accelerometer to measure vibration. Vibration analysis is defined as a process for measuring the vibration levels and frequencies of machinery and then using that information to analyze how healthy the machines and their components are. Read about vibration analysis methodology, tools and techniques, vibration analysis measurement methods, and more. Vibration analysis helps you monitor and detect issues using vibration data.
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