I carried out a vibration survey on a horizontally mounted pump.The motor gave its highest amplitude at 2x Line frequency with sidebands radially.The highest amplitude was 0.666mm/s in peak. This particular frequency extended to the pump and amplified to 7mm/s in peak.This 7mm/s peak is by far the highest and the closest is about 0.7mm/s on same spectra. Could resonance be the cause of the amplification or a pump rotor problem?

2x speed frequncy needs to be resolved with higher resolution to see wheather it is 2x speed or 2x line frequency before conclusion. If the vibrations are directional nature on horizontal direction there are various methods to resolve the same. for this all spectrums and over all vibrations on that equipmeent needs to be looked in