Vibration Testing
Accelerometer Mounting: The Detail That Sets Your Frequency Range
A short note on how the accelerometer mounting method determines the usable frequency range in vibration testing.
How an accelerometer is mounted is far more critical than most engineers assume. The mounting method directly sets the upper frequency limit at which the sensor can measure reliably.
Mounting Methods and Frequency Limit#
Approximate values (they vary by sensor):
- Stud mounting — the widest range; the only correct choice for most high-frequency measurements.
- Adhesive / beeswax — a medium range, quick to set up.
- Magnet — practical, but the upper frequency limit drops noticeably.
- Hand-held probe — for rough surveys only; poor repeatability.
The magnet trap
Magnetic mounting is very convenient for field measurements, but at high frequencies the mounting resonance can add a false peak to your measurement. If high-frequency content matters, switch to stud mounting.
Rule of Thumb#
Know the highest frequency you intend to measure and make sure the mounting method comfortably covers it. When in doubt, take a measurement at the same point with two different mountings and compare the spectra.