Vibration Analysis of a Diesel Generator Set Used in Small Commercial Establishments in Onitsha, Anambra State

Diesel generator sets constitute the primary electricity supply for commercial operations across many Nigerian cities due to chronic grid power shortages, yet their vibration characteristics and potential for structural damage to building foundations and mounting systems are rarely evaluated in local commercial contexts. This study presents a vibration analysis of a 10-kilowatt diesel generator set commonly deployed in small commercial establishments in Onitsha, Anambra State. Vibration measurements were conducted using a tri-axial accelerometer mounted at the generator base frame, engine block, and anti-vibration mounts under no-load, half-load, and full-load operating conditions. Frequency spectra were obtained through fast Fourier transform processing of the recorded time-domain acceleration signals. The analysis identified dominant vibration frequencies at 25 Hz and 50 Hz corresponding to engine firing frequency and its first harmonic, with peak acceleration amplitudes of 4.8 m/s squared recorded at the base frame under full load. Anti-vibration mounts reduced transmitted vibration to the mounting slab by approximately 68 percent across the dominant frequency range. Finite element analysis of the generator mounting frame confirmed that stress levels remained below fatigue limits under the recorded vibration loading. The study recommends standardised vibration isolation specifications for diesel generator installations in commercial buildings across urban South East Nigeria to prevent premature structural damage. Keywords: diesel generator, vibration analysis, frequency spectrum, anti-vibration mounts, Onitsha.