Vibration Source Identification: How to Find the Cause
Without Installing Sensors

Maintenance teams run into the same problem repeatedly: a sensor at a bearing housing shows elevated vibration, but nothing in the reading says where the energy actually originates. Is it the bearing itself? The coupling? The support frame a metre away? The connected piping? An FFT spectrum only confirms that something crossed a threshold — it does not show the mechanism or the location.

That distinction has direct practical consequences. Repairing the wrong component is expensive, time-consuming and — if the machine returns to service with the same unidentified source still active — ineffective. The faster and more confidently a team can locate the cause, the shorter the path from alarm to a repair that actually holds.

Why Point Sensors Struggle to Locate a Source

An accelerometer measures exactly what is happening at its mounting location, in one direction, at a given instant. A typical industrial machine carries one to four sensors, usually at the bearing housings. The coupling, support frame, baseplate, connected piping and adjacent structural elements are generally left uninstrumented.

That creates a spatial gap that can, in theory, be closed by adding more sensors. In practice this is an expensive and incomplete fix — there is no way to know in advance which additional location will actually turn out to be the source until it is measured.

What Phase Relationship Reveals About Direction

Beyond amplitude and frequency, phase carries information about direction and how components move relative to each other. When two coupled components — a motor and a pump, for example — move out of phase, that is a direct signature of misalignment. When a structural element rotates about a fixed edge instead of staying rigid, that is the signature of mounting looseness or a fatigued fastener.

These motion patterns are exactly what distinguishes one source from another — but they require measuring multiple points simultaneously to compare phase between them. A single sensor has nothing to compare against.

How Full-Field Measurement Locates the Source Directly

Vibration amplification measures the motion of every visible point on a structure simultaneously, not just one. Every pixel in the image acts as an independent virtual sensor. Instead of inferring a location indirectly from a single reading, the analyst sees directly which part of the machine or surrounding structure is actually moving, and how.

That reverses the order of the diagnostic process. Instead of: measure one point → compute a frequency → infer a possible cause → physically check each hypothesis, the process becomes: capture the whole area at once → see directly where the energy is concentrated → confirm the cause on-site.

Example: A Resonance a Sensor Missed

Structural resonance is one of the most commonly missed cases, because it raises overall vibration levels without generating a clear defect signature right at the sensor. A bearing sensor can read well within spec while the adjacent structure — a frame, a platform, a bracket — is resonating undetected nearby.

A full-field ODS reveals this immediately: the area of maximum deflection is visible directly in the video, along with the mode shape of the whole structure, not just a number at one point.

A Practical Process for Locating an Unknown Vibration Source

The sequence below combines both approaches into a single diagnostic workflow, from the first alarm to a confirmed root cause.

1. 01 Record the elevated vibration with a point sensor and confirm the threshold exceedance against ISO 10816 / 20816.
2. 02 If the spectrum does not point to a clear cause, position the VibraVizja® camera at a safe distance from the machine — no contact, no production stop.
3. 03 Record the amplified video at full operating load, framing the machine and the adjacent structure together.
4. 04 Identify directly on the image where the vibration energy is concentrated and what motion the location is exhibiting.
5. 05 Confirm the root cause and direct the repair exactly where it is needed — no trial and error.

Locating the source of vibration does not have to be a process of trial and error. When the spectrum does not give a clear answer, full-field measurement shows directly what no single sensor can capture: the exact location and mechanism you are actually dealing with.

Frequently Asked Questions