Guest post by Ray DeHerrera, Mechanical Engineer at Pioneer Engineering
Vibration analysts use multiple tools to predict a potential fault in a machine; from transducers to accelerometers, the toolbox for vibration analysts is continually expanding to allow for more comprehensive and accurate data collection and interpretation. One tool that is absolutely important to the data analysis process is knowing how your equipment processes data. Vibration analysts need to know how results are being derived from multiple calculations within your equipment. This allows for the development of an efficient collection history that will produce more accurate results.
The calculations attempt to translate data banks into a model that can then explain the events occurring inside of your equipment. Often times the computer-processed model may develop imaginary information, thus leading to more questions than answers. With basic background and knowledge of variables that may affect your post-processed data, your questions will start to be answered.
To introduce the initial creation of our mathematical model that is displayed upon our data collector or computer screen, (such as the time waveform or spectrum) we will explore commonly used hardware such as the transducer. In general, the function of the transducer is to convert one form of energy into another. A commonly used transducer for case-mounted readings is an accelerometer. The accelerometer mimics mechanical vibrations to produce a usable signal. The usable signal is so small that typically an internal amplifier will be needed for your data collector to harness the information. This process is the initial creation of our mathematical model of data, which has been created from a response of a mechanical device (transducer) sitting upon a machine and is now being converted to a digital signal that has been amplified.
Now our signal must be stored for further analysis. There are a number of vibration collector types and manufacturers. The collector is very similar to a computer giving it the ability to quickly process the original signal into various mathematical models. One must take the time to do their research before purchasing a collector and the associated software. Many desired post-processing and collection capabilities may be limited such as sampling rates. With a good collector and setup, your mathematical models will be accurate. The accuracy and consistency in your collections are key when managing your periodic collections.
The basic knowledge of how your equipment generates your post-processed model will make your time more efficient and your results accurate. The analyst will be able to identify data that is imaginary and pick out what is real. Take the time to understand your hardware and how your computer generates each model.