Coal Mining Cases

Event: Vibration at the air compressor motor measurement point began increasing slowly in early August. Noise was noticeably greater than that of motors of the same model. Maintenance personnel could not identify the cause and requested our analysis.

Diagnostic conclusion: Spectra in all three directions showed similar features, with high amplitudes at 25 Hz and 118.75 Hz. The 25 Hz component was particularly prominent, with a small 50 Hz component also visible. The analyst suspected relatively severe rotational unbalance and a bearing fault in the compressor motor.

Site verification: Maintenance personnel immediately replaced the air compressor bearing and confirmed severe wear.