Operating Life of Aluminum Electrolytic Capacitor

Approximately 300 aluminum electrolytic capacitors, which have been used for about 10 years in electronic switching systems, were examined to confirm any degradation by non-destructive and destructive analyses and to estimate operating life through the accelerated life test. No degradation in electrical performance, such as capacitance, dissipation factor (tan δ) and DC leakage current, was observed in non-destructive analysis before the accelerated test. Furthermore, evaporation (dry-up) of electrolyte, discoloration of separator paper and electrical chracteristics change in the electrode foil were not detected by dissection of the capacitors. Operating life for these capacitors was estimated to be sixteen years, taking into account empirical acceleration factor.