شلی مکانیکی — راهنما

Mechanical looseness: excessive clearance or improper fastening creates nonlinear impacts. FFT: Many harmonics 0.5X, 1X, 1.5X, 2X, 2.5X, 3X... Sub-harmonics (0.5X) are a strong indicator. High crest factor (>6 for severe cases). Broadband noise floor elevated. Types: Structural (baseplate), loose rotating element, internal bearing housing clearance. ⚠ Looseness can mask or combine with other faults. Physical inspection (tighten, check fits) is mandatory.