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