Integer multiples of the running speed (e.g., 2X, 3X), typically indicating mechanical issues like misalignment or unbalance.

Visual examples of FFT (Fast Fourier Transform) spectra for each fault, showing where peaks occur relative to the machine's running speed (e.g., 1X, 2X, 3X).

Frequencies that are not whole-number multiples, often signaling bearing defects or electrical faults. 2. Primary Fault Categories on Diagnostic Charts