Deriving Life Multipliers for Electrolytic Capacitors

Aluminum electrolytic capacitors are routinely used as input bus capacitors in the power supply sections of electronic equipment such as motor drives, UPS systems, and welders. Most of these capacitors fail eventually from wearout. This article offers a brief explanation of how capacitor manufacturers quantify the effects of applied voltage, ripple current, frequency, ambient temperature, and airflow on capacitor life. The general capacitor life equation is