Vibration analysis is the measurement and interpretation of machine vibration to detect faults in rotating equipment, such as imbalance, misalignment, looseness and bearing damage, before they cause failure.
Sensors, usually accelerometers, are mounted on bearing housings of motors, pumps, fans, gearboxes and compressors. Large machines with sleeve bearings often use non-contact proximity probes that measure shaft movement directly. Readings come from portable route-based collectors, permanently installed online systems or, increasingly, wireless sensors.
The raw signal is a time waveform of displacement, velocity or acceleration. A fast Fourier transform (FFT) converts it into a spectrum that shows how much vibration occurs at each frequency. Faults have characteristic frequencies relative to running speed: imbalance shows mainly at 1x running speed, misalignment often at 2x, and rolling-element bearing defects at specific frequencies set by bearing geometry. Overall velocity levels are compared with severity guidelines to decide whether a machine is acceptable, needs attention or should be stopped.
Vibration analysis is the core technique of condition monitoring for rotating machines, but interpretation takes skill. Sensor mounting, speed changes and nearby machines all affect readings. Low-cost wireless sensors often report only overall levels or sample infrequently, which catches late-stage faults but can miss early bearing defects. Machine-learning tools can flag abnormal spectra, but a trained analyst usually confirms the diagnosis.
Common faults and where they show in the vibration spectrum
| Fault | Characteristic frequency |
|---|---|
| Imbalance | Mainly at 1x running speed |
| Misalignment | Often at 2x running speed |
| Rolling-element bearing defects | Specific frequencies set by bearing geometry |
Questions about Vibration analysis
What does an FFT do in vibration analysis?
A fast Fourier transform converts the raw time waveform into a spectrum that shows how much vibration occurs at each frequency. Faults have characteristic frequencies relative to running speed: imbalance shows mainly at 1x running speed, misalignment often at 2x.
Are low-cost wireless vibration sensors enough?
Not always. They often report only overall levels or sample infrequently. That catches late-stage faults but can miss early bearing defects.
Is vibration analysis the same as condition monitoring?
No. Vibration analysis is one condition monitoring technique, the core one for rotating machines. Condition monitoring also covers infrared thermography, oil and wear-debris analysis, ultrasound and motor current signature analysis.
Vibration analysis in real plants
- Domtar and Waites: Domtar monitors equipment at its Kingsport, Tennessee mill with 748 Waites AI-assisted vibration sensors, with a Waites analyst and the mill reliability team reviewing alerts.
- Cadillac Casting and Tractian: Cadillac Casting replaced manual vibration routes with Tractian continuous monitoring on critical assets at its 280,000 square foot foundry in Michigan.
- Unilever and Tractian: A Unilever food plant in Latin America deployed Tractian condition monitoring from June 2025: 320 sensors on 40 critical assets, with expansion to 520 sensors planned.
- Danone and Tractian: Danone implemented Tractian condition monitoring on critical assets of a dairy plant, such as homogenizers, pumps and compressors.
- Pirelli and Tractian: Pirelli deployed Tractian condition monitoring sensors on critical assets at a tire plant with 2,800 people, with weekly monitoring reviews.
Vendors linked to Vibration analysis
Tractian (7) · AssetWatch (4) · KCF Technologies (4) · Waites (2) · Emerson (1) · Petasense (1) · Augury
Related terms
Condition monitoring
Condition monitoring is the ongoing measurement of machine parameters such as vibration, temperature, or oil quality to detect significant changes that indicate a developing fault.
Predictive maintenance
Predictive maintenance is maintenance triggered by a prediction of failure, based on measured equipment condition such as vibration, temperature, or noise.
Prescriptive maintenance
Prescriptive maintenance is a maintenance approach that goes beyond predicting when equipment will fail and recommends what action to take, when, and with which resources to prevent or limit the failure.
Anomaly detection
Anomaly detection is the identification of observations or patterns that deviate significantly from normal behavior in data.
Industrial IoT (IIoT)
Industrial IoT (IIoT) is the network of sensors, instruments, and machines in industrial settings that are connected to computers and software to collect and use operational data.