Diagnostics & analysis

Last reviewed 30 May 2026

Vibration troubleshooting guide

This guide is a step-by-step decision tree that will help you systematically pin down the cause of vibration in your equipment. Work through it step by step, answering the questions, to arrive at a precise "diagnosis" and choose the right "treatment".

Before you begin: make sure the equipment has been cleaned of dirt, all fastenings are tight, and the bearings are lubricated and free of critical wear.

Step 1: Measure the vibration spectrum

The first and most important step is to capture a vibration spectrum with a vibration analyser (such as the Balanset-1A). Take measurements in the radial (horizontal) and axial directions on the bearing housings.

Your key question: which peak in the spectrum is the tallest?

Step 2: Analyse the dominant peak

Question: does the peak at the rotational frequency (1×) dominate?

Compare the height of the peak at the rotational frequency (e.g. 25 Hz for 1500 rpm) with the other peaks.

  • Yes, the 1× peak is clearly higher than the rest. Go to Step 3.
  • No, the tallest peak is at a different frequency. Go to Step 4.

Step 3: The problem is linked to the rotational frequency (1×)

If 1× dominates, the most likely cause is imbalance. Before balancing, you must rule out mechanical looseness.

Question: are multiple harmonics (2×, 3×, 4×...) present in the spectrum?

Look at the whole spectrum. Do you see a "forest" of peaks at frequencies that are multiples of the rotational frequency?

  • Yes, a "forest" of harmonics is visible. Your problem is mechanical looseness. SOLUTION: stop the machine and carefully tighten every bolted connection: the bearing fixings, the motor feet and the foundation anchor bolts. Then take the measurement again.
  • No, the 1× peak is clean and the harmonics are low. Your problem is imbalance. SOLUTION: carry out dynamic rotor balancing.

Step 4: The problem is NOT linked to the rotational frequency

If the tallest peak is not at 1×, look for other faults.

Question: is the dominant peak at 2× the rotational frequency, especially in the axial direction?

Compare the spectra taken in the radial and axial (along the shaft) directions.

  • Yes, the 2× peak is high, especially in the axial direction. Your problem is shaft misalignment. SOLUTION: balancing will not help! You need to align the shafts of the motor and the driven machine (pump, fan).
  • No, the 2× peak does not dominate. Go to Step 5.

Step 5: Analyse the non-synchronous peaks

Question: are there peaks at high frequencies that are not multiples of the rotational frequency?

Look for peaks in the mid and high-frequency range of the spectrum that are not harmonics (for example at 113 Hz or 137 Hz when the rotational frequency is 25 Hz).

  • Yes, there is a series of non-synchronous peaks. Your problem is a rolling-element bearing fault. SOLUTION: check the lubrication. Start planning to replace the bearing. Increase the monitoring frequency to track how quickly the fault is developing.
  • No, none of the above fits. If none of the steps has helped, you probably have a complex problem or a fault that requires advanced diagnostics by a specialist (for example electromagnetic problems, gearbox faults or cavitation).

Professional vibration diagnostics

If the decision tree didn't help, our specialists can carry out advanced diagnostics

The Balanset-1A instrument

Carry out diagnostics yourself with our vibration analyser.

Buy the instrument

Diagnostics services

Our specialists will help you pinpoint the exact cause of the vibration.

Request the service
Message us on WhatsApp

Quick checklist

  • Clean, tighten and lubricate before measuring
  • Capture spectra radially and axially on bearings
  • Check if the 1x peak dominates
  • If 1x plus harmonics, tighten bolts (looseness)
  • If 2x axial dominates, align the shafts
  • If non-synchronous peaks, plan bearing replacement
Next stepApply the matched fix; request diagnostics service for complex faults.