Broken Rotor Bar
Rotor bar defect — 50 Hz supply
500 KW motor at 1480 RPM, 4 poles, 28 rotor bars, 50 Hz supply. Velocity peaks: 4.2 mm/sec at 24.67 Hz (1x), sidebands at 21.2 Hz and 28.1 Hz. Radial horizontal measurement.
Stator Eccentricity
Dynamic eccentricity — 100 Hz dominant
200 KW motor at 2960 RPM, 2 poles, 50 Hz supply. High vibration at 100 Hz (2xFs) with sidebands at 50.7 Hz and 149.3 Hz. Velocity 6.8 mm/sec RMS. Radial direction.
Mechanical Looseness
Multiple harmonics — 5 peaks pattern
75 KW motor at 1450 RPM, 4 poles, 50 Hz supply. Peaks at 24.2, 48.4, 72.5, 96.7 and 120.8 Hz. Overall vibration 7.0 mm/sec RMS at drive end. Radial vertical.
High Vibration — Sleeve Bearings
Large motor — hydrodynamic bearings
3000 KW motor at 1500 RPM, 4 poles, 50 Hz supply, hydrodynamic bearings. Vibration 45 microns peak-to-peak at 1x. Describe diagnostic steps and acceptance check.