Relate excitation to speed

A rotation-linked excitation changes frequency as speed changes, while a structural mode has its own characteristics under the actual assembly conditions. A strong response near a crossing is one possible explanation for a narrow band. Other mechanisms or data-processing effects can also concentrate the observed result. A single operating point cannot establish a complete response curve or a safe speed boundary for the machine.

Check the measured response

The analysis needs reliable speed association, sensor location, measurement bandwidth and enough available observations around the reported condition. A change after sensor mounting or filtering can alter the apparent peak. Physical changes to mounts, covers or other components can also affect the response. SKF distinguishes several complementary vibration methods; none makes a narrow peak self-explanatory without the actual geometry and operating evidence.

If the same narrow band changes after a support or attachment change, the altered system response deserves review. If the band is unchanged but excitation increases, the forcing question differs. Neither comparison establishes a safe operating band without the actual engineering assessment.

Request engineering interpretation before intervention

Ask whether the available evidence supports a modal or forcing investigation and what component condition should be checked. Do not perform an improvised speed sweep, skip a speed band or alter control limits to investigate. A software restriction and a physical correction address different questions and both require approval applicable to the actual design. No MARSTON natural frequency, prohibited speed range or vibration limit is established here.