The effects of environmental contaminants on electronic power supplies

An often overlooked, but nonetheless critical, factor in the performance and reliability of electronic power supplies is the purity of the operating environment and cooling air. Even environments typically considered "clean" contain dust, soot, gases and salt. Additionally, varying levels of humidity and condensation must be taken into consideration, both alone and in combination with contaminants. This article explores the numerous negative effects of contamination, focusing primarily on the effect on thermal management characteristics and the degradation of electrical performance. Using existing Ascom products as "case studies", conclusions may be drawn regarding the effect of contaminants on life expectancy and failure rates. The authors illustrate how traditionally calculated MTBF numbers may be invalid if the cleanliness of the operating environment is not adequately addressed. Finally, they look at design and manufacturing solutions that may be implemented to reduce the harmful effects of contamination.