Introduction
Vibration measurements have been used to reliably diagnose performance problems in machinery and related mechanical products. A vibration data collector can be used effectively to measure and analyze the machinery vibration content in gearboxes, engines, turbines, fans, compressors, pumps and bearings. Ideally, a machine will have little or no vibration, indicating that the rotating components are appropriately balanced, aligned, and well maintained. Quick analysis and assessment of the vibration content can lead to fault diagnosis and prognosis of a machine’s ability to continue running. When compared to historical vibration data, vibration measurements can be used to pinpoint mechanical defects such as unbalance, misalignment, resonance, and part loosening.

Collecting Vibration Data
During vibration condition monitoring, the data from the rotating machinery is collected, stored, interpreted, and then compared with historical vibration measurements. Depending on the machine, the vibration data may be gathered using two different techniques. Vibration measurements on larger machines are taken using permanently attached transducers (accelerometers). For smaller machines (with hard-to-reach locations), vibration data is taken using handheld data collectors with portable transducers. The data is then stored and analyzed to determine the machine’s mechanical condition.

Analyzing Vibration Data
Vibration measurements can be expressed in terms of displacement, velocity, acceleration, and high frequency content (for bearing condition detection). Most data collectors use FFT (Fast Fourier Transform) to convert the data from the time domain to the frequency domain. Vibration data collectors have a built-in PC interface that allows transfer of the measurements to a PC for data management. Analysis software displays spectrum, trend, waterfall plots, and waveform for advanced analysis. To assess a machine, the vibration data is compared with historical profiles from the same machine.

Vibration Data Collector Features
Quick, accurate diagnosis of machine vibration conditions, including bearing vibration
Simplifies the task and increases the speed of collecting vibration monitoring data
Incorporates the latest software for vibration data analysis and performance prediction
Combines basic analysis functions and rotating machinery balancing capabilities
Lightweight, compact portable vibration data collectors are easy to use
Used with a portable computer, such as a laptop or notebook
Multiple channel models are available
Usually do not require any special training

Vibration Analysis Introduction
Vibration analysis training is a necessary process for engineers and technicians who desire to understand the vibration that exists in structures and machines. There are two types of vibration analysis tasks that are regularly done today. The first involves predicting the mechanical vibration that will exist in new products. The second involves evaluating the vibration that occurs in rotating machinery such as motors, pumps, and compressors. Advances in technology have greatly enhanced the vibration analysis process for both new and existing products. It is important for professionals in the vibration industries to keep up with the state-of-the-art in vibration analysis techniques.

Vibration Analysis Basics
Whether you are predicting the vibratory response of a new product, or you are analyzing the vibration that occurs in an existing product, vibration analysis is the study of resonance. Resonance occurs at specific frequencies (natural frequencies), where the vibration of the product is increased. Called modal analysis, this process is crucial to understanding the vibration behavior of any product. Once the fundamentals of vibration analysis are learned, vibration analysis training can proceed to more complicated topics, such as finite element analysis.

Finite Element Analysis
Finite element analysis (FEA) is normally used for vibration analysis of new product designs. This method allows the analyst to consider real-world structures that cannot be analyzed with elementary vibration analysis training. Using FEA for vibration analysis involves dividing the structure into a number of elements, and then performing a modal analysis. Using a defined vibration excitation (random vibration, for instance), FEA software is then used to predict the vibratory stresses in the structure. Vibration in existing machinery is analyzed with vibration analysis equipment and integrated software.

Machinery Vibration Measurement
Vibration analysis training is necessary for analyzing and evaluating the mechanical vibration that occurs in rotating machinery, such as motors, pumps, and bearings. Today’s vibration measurement equipment utilizes software that simplifies the analysis of machinery vibration performance. Multiple vibration data parameters are assessed to predict machinery operation. Called vibration condition monitoring, this procedure involves processing large quantities of data to determine if unscheduled maintenance is necessary, or if shutdown is required.