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Condition monitoring of electrolytic capacitors

Research paper by Acácio M. R. Amaral, A. J. Marques Cardoso

Indexed on: 02 Mar '12Published on: 02 Mar '12Published in: International Journal of System Assurance Engineering and Management



Abstract

This paper presents a very simple and cheap off-line technique that is able to evaluate the aluminum electrolytic capacitors condition. Aluminum electrolytic capacitors equivalent circuit is composed by an internal resistance and a capacitance. The capacitors internal resistance increases with aging while the capacitance decreases. Manufacturers define the end of life limit of the capacitor when its internal resistance doubles its initial value or the capacitance changes more than 20% when it is compared with the initial one. The proposed technique evaluates the capacitor condition through the identification of both capacitor internal resistance and capacitance. To compute both capacitor internal resistance and capacitance a very simple, cheap, and practical experimental setup is proposed.