Enhancing Ship Generator Reliability by Modifying Bearings to Prevent Electrical Arcing Damage

Stray electrical currents in marine generators cause catastrophic bearing fluting, leading to frequent failures and operational downtime. The harsh maritime environment exacerbates this issue, demanding a more robust solution than conventional methods. This study introduces an innovative porcelain insulation sleeve applied to the bearing housing of a 250 kVA ship generator. Its effectiveness was evaluated through comparative in-situ testing, measuring vibration, temperature, and electrical parameters under a 22 kW load, with insulation thicknesses varying from 2.0 mm to 2.75 mm. The porcelain armor performed exceptionally. A 2.20 mm thickness was identified as optimal, achieving a 94% reduction in vibration and a 3.7 °C drop in operating temperature. Critically, the insulation's ultra-high insulation resistance (1000 GΩ) completely blocked the path of parasitic currents, eliminating the root cause of electrical arcing and fluting damage. This work demonstrates that applying porcelain insulation provides a definitive, maintenance-free solution to bearing fluting. The research validates a highly effective and practical engineering intervention that significantly enhances the reliability, safety, and service life of marine generators.