Increased MTBF and Decreased Maintenance Cost by using systems without fans

This paper describes the advantages of power supply without fan in telecommunication systems. Reliability engineering focuses on design rules using high quality components and avoiding components with lifetimes shorter than service life of the power supply system. Convection cooling avoids high temperature levels, high temperature rise and too compact design. The focus is low maintenance effort, long service life, low stress, moderate utilization for general long life time. For these applications Gustav Klein has developed power system solutions with no need of regular maintenance within lifetime. Natural cooled Rectifiers, Inverters, DC/DC-Converters, Frequency-Converters and Uninterruptable Power Supplies are available up to 80kW respectively 80kVA. Natural cooled Power Supplies needs more powerful components, but a smaller quantity. The low quantity of components and the low temperatures increases the MTBF. Convection cooling uses low air speeds and needs in most applications no filtered air. Heat sinks with low temperature differences are in full operation even when they are covered with dust. So maintenance effort is in most applications a simple visual check.