What could excessive vibration at 2X indicate?

Excessive vibration at a frequency of 2X typically suggests a problem with misalignment in machinery. When the shafts of rotating equipment are misaligned, it can cause certain frequencies of vibration to manifest, particularly at harmonics of the rotational frequency. In this case, 2X refers to double the fundamental rotational frequency (1X).

This misalignment can arise in various configurations, including parallel misalignment or angular misalignment. The imbalance of forces created by the misalignment leads to vibration that is significant enough to be detected at this harmonic frequency. While other issues such as unbalance, loose parts, or rotating looseness can cause vibrations, their signature frequencies are typically different and do not specifically lead to pronounced 2X vibrations. Thus, recognizing 2X vibration as a key indicator of misalignment is crucial for diagnosing and addressing the underlying mechanical issues effectively.