Vibration meters

A mechanical vibration is the periodic movement of a component about its rest position. It can be described by three physically interrelated parameters, each suited to a different frequency range and a different question:

Vibration acceleration (a, in m/s²)
Acceleration evaluates the forces acting on the component and reacts particularly sensitively to high-frequency vibration components. It is the right quantity for detecting incipient rolling-bearing and gear-tooth damage (typical range approx. 1 kHz to 15 kHz). The peak value is usually displayed.

Vibration velocity (v, in mm/s)
Vibration velocity is the central quantity for assessing the general running condition of a machine. It is measured as an RMS value in the frequency range from about 10 Hz to 1 kHz and forms the basis of the evaluation zones according to ISO 10816 / ISO 20816 (evaluation of machine vibration by measurements on non-rotating parts). Rising RMS values directly indicate a deterioration of the machine condition.

Vibration displacement (s, in mm)
Displacement describes the actual deflection of the component and is meaningful in the low-frequency range (approx. 10 Hz to 500 Hz). It is given as a peak-to-peak value and is particularly suitable for assessing unbalance and slow, low-frequency movements, for example on slow-running machines.

Acceleration, velocity and displacement are mathematically linked via frequency (integration or differentiation). Which parameter provides the best information in a given case therefore depends on the speed and the expected damage pattern. An instrument that captures all three quantities covers the entire spectrum from unbalance to bearing damage.

Our vibration meters work with a piezoelectric acceleration sensor. The measuring tip of the instrument is pressed firmly against the non-rotating machine housing by hand – as close as possible to the bearing and in the direction of the expected vibration (radial or axial). The sensor converts the vibration into an electrical signal, which is filtered and integrated in the instrument and – depending on the selected parameter – displayed as acceleration, velocity or displacement. After the measurement, the reading is held for 15 seconds so that it can be read comfortably even in hard-to-reach places; the instrument then switches off automatically.

For a reliable condition assessment, it is advisable to carry out the measurements regularly at the same marked measuring points and under comparable operating conditions (speed, load, temperature). From the trend of the readings over time, an emerging fault can be detected considerably earlier than from a single reading.

• Maintenance and preventive servicing of electric motors, fans, pumps, compressors and gearboxes
• Quick check of unbalance, misalignment as well as bearing and gear damage
• Acceptance and functional testing in production, workshop and service
• Monitoring of machine tools and drives