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Measuring Vibration
Last Updated: 08/09/2017

Measuring Vibration

Measuring vibration using modern vibration sensors is relatively inexpensive and easy to do! Knowing the vibration levels of rotating machinery and related accessories will allow you to make informed decisions as to the health of a machine and its components.

Measuring vibration may be as simple as purchasing a vibration meter with a handheld accelerometer and then comparing the reading to the ISO-10816 vibration severity chart! The vibration meter will integrate the accelerometer signal to velocity in in/sec or mm/sec. Decisions can then be made as to whether the machine needs balancing, alignment or even bearing replacement.

Vibration Meters

Vibration Meter

Vibration is transmitted from the rotating shaft of a machine through the bearings to the bearing caps. For this reason vibration measurement is usually done at the bearing caps. In most cases, especially with machines using Rolling Element Bearings, accelerometers or velocity sensors are preferred as all rotating shaft vibration energy is transmitted directly to the bearing cap. Machines with Journal Bearings may be better monitored using installed proximity probes connected to full time monitoring as not all vibration is transmitted to the bearing cap due to bearing damping.

ISO-10816-3 Vibration Severity Chart

For more critical machinery, Accelerometers or Velocity Sensors can be permanently mounted on the machine’s bearing caps and wired to local Vibration Transmitters, which supply a 4-20 mA signal proportional to the vibration measurement to the plant’s PLC or DCS for alarming and continuous monitoring by the plant operators.

Vibration Transmitters

Vibration Transmitters

Growth Stages of Vibration Measurement Programs by Complexity:

1. Vibration Meter (Compare Readings to ISO-10816)
2. Critical Machinery (Full Time Monitoring using Transmitters or Monitors)
3. Vibration Analyzer (Spectrum/Frequency Information for Diagnostics)
4. PMP Program (Predictive Maintenance Program, Data Collector/Analyzer/Software)
5. Permanently Mounted Sensors and BNC Junction Boxes to Speed Collection

Having a Vibration Measurement Program will increase reliability, reduce spare parts and allow you to plan more effectively. For help with your application or if you have any questions drop us an email or give us a call!

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